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JPWO2013058237

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JPWO2013058237
The dielectric film of the present invention comprises an elastomer and barium titanate particles
having a crystallinity of 80% or more. The elastomer and the barium titanate particles have
functional groups capable of reacting with each other, and a reaction between the functional
groups forms a crosslinked structure of the elastomer and the barium titanate particles. For this
reason, the dielectric constant and volume resistivity of the dielectric film of the present
invention are large. The transducer of the present invention also includes the dielectric film and a
plurality of electrodes disposed via the dielectric film. The transducer of the present invention is
excellent in resistance to breakdown and can output a large force.
Dielectric film and transducer using the same
[0001]
The present invention relates to a transducer using an elastomeric material, and more
particularly to a dielectric film used in the transducer.
[0002]
As the transducer, an actuator that converts mechanical energy and electrical energy, a sensor, a
power generation element, or a speaker that converts acoustic energy to electrical energy, a
microphone, and the like are known.
Polymeric materials such as dielectric elastomers are useful for constructing a flexible, compact
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and lightweight transducer.
[0003]
For example, as described in Patent Document 1, an actuator can be configured by arranging a
pair of electrodes on both sides in the thickness direction of a dielectric film made of a dielectric
elastomer. In this type of actuator, increasing the voltage applied between the electrodes
increases the electrostatic attraction between the electrodes. Therefore, the dielectric film
sandwiched between the electrodes is compressed from the thickness direction, and the
thickness of the dielectric film becomes thin. As the film thickness becomes thinner, the dielectric
film elongates in a direction parallel to the electrode surface. On the other hand, when the
voltage applied between the electrodes is reduced, the electrostatic attraction between the
electrodes is reduced. For this reason, the compressive force on the dielectric film in the
thickness direction is reduced, and the elastic restoring force of the dielectric film increases the
film thickness. As the film thickness increases, the dielectric film contracts in a direction parallel
to the electrode surface. Thus, the actuator drives the driven member by stretching and
contracting the dielectric film.
[0004]
In order to increase the amount of force and displacement output from the actuator, it is
necessary to increase the relative permittivity and volume resistivity of the dielectric film. For
this reason, as a material of the dielectric film, acrylic rubber, nitrile rubber, silicone rubber or
the like which is excellent in dielectric breakdown resistance is used.
[0005]
JP-A-2003-506858 JP-A-2009-227985 JP-A-2011-084712 JP-A-2005-306691
[0006]
The silicone rubber has a siloxane bond as a skeleton.
Therefore, the electrical resistance is large. Therefore, the dielectric film made of silicone rubber
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is unlikely to be broken down even if a large voltage is applied. However, the polarity of silicone
rubber is small. That is, the relative dielectric constant is small. For this reason, when the
actuator is configured using a dielectric film made of silicone rubber, the electrostatic attraction
to the applied voltage is small. Therefore, due to the practical voltage, desired force and
displacement can not be obtained.
[0007]
On the other hand, the dielectric constant of acrylic rubber and nitrile rubber is larger than the
dielectric constant of silicone rubber. For this reason, when acrylic rubber or the like is used as
the material of the dielectric film, the electrostatic attraction with respect to the applied voltage
is larger than that in the case of using silicone rubber. However, the electrical resistance of
acrylic rubber or the like is smaller than that of silicone rubber. Therefore, the dielectric film is
prone to dielectric breakdown. In addition, when a voltage is applied, a current flows in the
dielectric film (so-called leakage current), and charge is unlikely to be accumulated near the
interface between the dielectric film and the electrode. Therefore, although the relative dielectric
constant is large, the electrostatic attraction becomes small, and a sufficient amount of force and
displacement can not be obtained. Thus, with an elastomer alone, it is difficult to realize a
dielectric film that satisfies both electrostatic attraction and dielectric breakdown resistance.
[0008]
In this respect, Patent Document 2 discloses a dielectric film in which a high dielectric ceramic
powder such as barium titanate is blended in a base rubber. In addition, the inventor of the
present invention has developed, as a material of a dielectric film, an elastomer material in which
an inorganic filler such as barium titanate is blended in an elastomer crosslinked with an organic
metal compound (see Patent Document 3). When an inorganic filler is added to the elastomer, the
flow of electrons is thereby blocked, and the electrical resistance can be increased. However, in
conventional elastomeric materials, the inorganic filler is not directly chemically bonded to the
elastomer. For this reason, an insulation network can not be formed by the combination of the
elastomer and the inorganic filler, and the effect of increasing the electrical resistance is not
sufficient. In addition, when a voltage is applied, a discharge occurs in a minute gap between the
elastomer and the inorganic filler, which may result in a decrease in the dielectric breakdown
resistance. Moreover, the barium titanate compounded as an inorganic filler has a large dielectric
constant and volume resistivity, so that crystallinity is high. However, in the patent documents 2
and 3 mentioned above, the examination about the crystallinity of barium titanate is not carried
out.
05-05-2019
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[0009]
The present invention has been made in view of such circumstances, and it is an object of the
present invention to provide a dielectric film having a large relative dielectric constant and
volume resistivity. Another object of the present invention is to provide a transducer which is
excellent in resistance to dielectric breakdown and can output a large force by using the
dielectric film.
[0010]
(1) The dielectric film of the present invention is a dielectric film used for a transducer, and
comprises an elastomer and barium titanate particles having a crystallinity of 80% or more, and
the elastomer and the barium titanate particles are It has a functional group capable of reacting
with each other, and the reaction between the functional groups is characterized in that a
crosslinked structure is formed by the elastomer and the barium titanate particles.
[0011]
In the dielectric film of the present invention, a crosslinked structure of an elastomer and barium
titanate particles is formed.
That is, the flow of electrons is blocked by the insulating network formed of the elastomer and
the barium titanate particles. For this reason, the electrical resistance of the dielectric film of the
present invention is large. Further, the elastomer and the barium titanate particles are chemically
bonded. For this reason, there is no gap between the two. Therefore, at the time of voltage
application, dielectric breakdown due to discharge hardly occurs. Also, barium titanate particles
are incorporated into the three-dimensional network structure of the elastomer. For this reason,
barium titanate particles do not easily aggregate. That is, the barium titanate particles are
uniformly dispersed in the elastomer in the form of single primary particles rather than
aggregated secondary particles. Therefore, the passage of electrons can be inhibited more
effectively. Also, the film quality of the dielectric film is uniform. Therefore, the extension of the
dielectric film at the time of voltage application becomes uniform, and it is difficult to cause the
dielectric breakdown based on the barium titanate particles.
05-05-2019
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[0012]
Here, the crystallinity of the barium titanate particles is 80% or more. Because of the high
crystallinity, the relative dielectric constant and volume resistivity of barium titanate particles are
large. By using barium titanate particles having high crystallinity, the dielectric constant and
volume resistivity of the dielectric film of the present invention can be further increased. The
degree of crystallinity can be measured by an X-ray diffraction (XRD) apparatus. That is, if the
obtained XRD pattern is separated into the peak intensity generated from the crystalline
component and the intensity of the halo generated from the amorphous component, and the
integrated intensity is used to calculate by the following equation (1) Good. Degree of
crystallinity (%) = Sc / (Sc + Sa) × 100 (1) [Sc: integrated intensity of crystal peak, Sa: integrated
intensity of amorphous halo] Thus, barium titanate having high crystallinity By using the
particles to form a cross-linked structure of the barium titanate particles and the elastomer to
disperse the barium titanate particles uniformly in the elastomer, the dielectric constant and the
volume resistivity of the dielectric film are significantly improved. It can be done. According to
the dielectric film of the present invention, the electrostatic attraction with respect to the applied
voltage is large because the relative dielectric constant is large. In addition, since the volume
resistivity is large, the leakage current is reduced, and a large amount of charge can be
accumulated near the interface between the dielectric film and the electrode. Therefore,
according to the transducer provided with the dielectric film of the present invention, a large
amount of force and displacement can be obtained by practical voltage. In addition, the dielectric
film of the present invention has high resistance to dielectric breakdown. Therefore, a larger
voltage can be applied to obtain a larger amount of force and displacement.
[0013]
(2) Further, the transducer of the present invention is characterized by comprising the dielectric
film of the present invention and a plurality of electrodes disposed via the dielectric film.
[0014]
The transducer of the present invention comprises the dielectric film of the present invention.
As described above, the dielectric constant and volume resistivity of the dielectric film of the
present invention are large. Therefore, when a voltage is applied to the dielectric film of the
present invention, a large electrostatic attraction is generated. Therefore, according to the
transducer of the present invention, a large amount of force and displacement can be obtained by
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a practical voltage. In addition, since the dielectric film has high resistance to dielectric
breakdown, a larger voltage can be applied to obtain a larger force and displacement.
[0015]
It is a cross-sectional schematic diagram of the actuator which is 1st embodiment of the
transducer of this invention, Comprising: (a) shows a voltage OFF state, (b) shows a voltage ON
state. It is a front side front view of an actuator attached to a measuring device. It is the III-III
sectional view of FIG. It is a perspective view of the speaker which is a second embodiment of the
transducer of the present invention. It is a V-V cross-sectional view of FIG.
[0016]
1: Actuator (transducer), 10: dielectric film, 11a, 11b: electrode, 12a, 12b: wiring, 13: power
supply. 4: Speaker (transducer) 40a: first outer frame 40b: second outer frame 41a: first inner
frame 41b: second inner frame 42a: first dielectric film 42b: second dielectric film 43a : First
outer electrode, 43b: second outer electrode, 44a: first inner electrode, 44b: second inner
electrode, 45a: first diaphragm, 45b: second diaphragm, 430a, 430b, 440a, 440b: terminal , 460:
bolt, 461: nut, 462: spacer. 5: actuator, 50: dielectric film, 51a, 51b: electrode, 52: upper chuck,
53: lower chuck.
[0017]
Hereinafter, embodiments of the dielectric film and the transducer of the present invention will
be described. The dielectric film and the transducer according to the present invention are not
limited to the following embodiments, and various modifications can be made without departing
from the scope of the present invention, and various modifications and improvements can be
made by those skilled in the art. It can be implemented.
[0018]
<Dielectric Film> The dielectric film of the present invention contains an elastomer and barium
titanate particles having a crystallinity of 80% or more.
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[0019]
[Elastomer] The elastomer is not particularly limited as long as it has a functional group capable
of reacting with the functional group of barium titanate particles.
As described later, the functional group of the barium titanate particle contains at least one of an
alkoxy group (-OR) and a hydroxy group (-OH). Therefore, functional groups capable of reacting
with these functional groups, specifically, hydroxy group (-OH), amino group (-NH2, -NHR1, NR1R2), carboxy group (-COOH), Those having one or more selected from a thiol group (-SH) and
a halogenated alkyl group (-RX) are desirable (R, R 1 and R 2 are alkyl groups, and X is a halogen
atom).
[0020]
Elastomers include crosslinked rubbers and thermoplastic elastomers. These may be used alone
or in combination of two or more. The elastomer may be selected appropriately according to the
performance required for the transducer. For example, an elastomer having a large polarity, that
is, a large dielectric constant, is desirable from the viewpoint of increasing the electrostatic
attraction generated when a voltage is applied. Specifically, one having a relative dielectric
constant of 2.8 or more (measurement frequency 100 Hz) is preferable. As an elastomer having a
large dielectric constant, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR),
acrylic rubber, natural rubber, isoprene rubber, ethylene-vinyl acetate copolymer, ethylene-vinyl
acetate-acrylic Examples thereof include acid ester copolymers, butyl rubber, styrene-butadiene
rubber, fluororubber, epichlorohydrin rubber, chloroprene rubber, chlorinated polyethylene,
chlorosulfonated polyethylene, and urethane rubber. When the elastomer does not have a
functional group, it may be modified by introducing a functional group or the like. As the
modified elastomer, for example, carboxyl group-modified nitrile rubber (X-NBR), carboxyl groupmodified hydrogenated nitrile rubber (XH-NBR) and the like are preferable. In X-NBR and XHNBR, those having an acrylonitrile content (an amount of bonded AN) of 33% by mass or more
are desirable. The bonded AN amount is a mass ratio of acrylonitrile when the total mass of the
rubber is 100% by mass.
[0021]
Moreover, even if the relative dielectric constant is small, an elastomer having a large electric
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resistance is desirable in that it is difficult to cause dielectric breakdown when a voltage is
applied. As an elastomer with a large electric resistance, silicone rubber, an ethylene-propylenediene copolymer, etc. are mentioned. When the elastomer does not have a functional group, a
functional group may be introduced as appropriate.
[0022]
Moreover, since a thermoplastic elastomer does not use a crosslinking agent, it is hard to contain
an impurity and it is suitable. As thermoplastic elastomers, styrene-based (SBS, SEBS, SEPS),
olefin-based (TPO), polyvinyl chloride-based (TPVC), urethane-based (TPU), ester-based (TPEE),
amide-based (TPAE), and co-polymers thereof Polymers and blends may be mentioned.
[0023]
[Barium Titanate Particles] As barium titanate particles, those having a crystallinity of 80% or
more are used. Moreover, the barium titanate particles produced by the production method
described later have at least one of an alkoxy group (-OR) and a hydroxy group (-OH) on the
surface as a functional group capable of reacting with the functional group of the elastomer. . By
reacting the functional group of the barium titanate particle with the functional group of the
elastomer, a crosslinked structure is formed. That is, barium titanate particles play a role as a
crosslinking agent.
[0024]
In consideration of the uniformity of the dielectric film, the particle diameter of the barium
titanate particles is preferably smaller. By uniformly dispersing the barium titanate particles
having a small particle size in the elastomer, a dense insulating network is formed. In addition,
the film quality of the dielectric film becomes uniform. Therefore, the leakage current at the time
of voltage application is suppressed, the extension of the dielectric film becomes uniform, and it
is difficult to cause the dielectric breakdown based on the barium titanate particles. On the other
hand, the relative dielectric constant of barium titanate increases as the particle size increases.
Therefore, in consideration of the dielectric constant of the dielectric film, it is desirable that the
particle diameter of the barium titanate particles be larger. Therefore, the particle diameter of the
barium titanate particles may be appropriately determined so that the dielectric film has desired
dielectric constant, volume resistivity, flexibility, etc., in consideration of these contradictory
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advantages.
[0025]
For example, the particle diameter of barium titanate particles is preferably 8 nm or more and
120 nm or less. When the particle diameter is less than 8 nm, the effect of increasing the relative
dielectric constant is reduced. 10 nm or more is suitable. When the particle diameter exceeds
120 nm, the effect of increasing the volume resistivity decreases. 60 nm or less is suitable.
[0026]
In the present specification, unless otherwise specified, the median diameter is adopted as the
particle diameter of barium titanate particles. The particle diameter of the barium titanate
particles in the dielectric film can be measured by observation using a transmission electron
microscope (TEM). Also, it may be measured by a scanning probe microscope (SPM), small angle
X-ray scattering method, X-ray diffraction (XRD).
[0027]
As described later, barium titanate particles can be produced by a sol-gel method using a high
concentration of precursor. In this case, the particle diameter of the barium titanate particles in
the obtained gel is presumed to be equal to the particle diameter of the barium titanate particles
in the dielectric film. Therefore, the particle diameter of the barium titanate particles in the gel
may be adopted as the particle diameter of the barium titanate particles in the dielectric film. The
particle diameter of the barium titanate particles in the gel can be measured, for example, using a
laser diffraction / scattering particle diameter / particle size distribution measuring device
manufactured by Nikkiso Co., Ltd. Alternatively, the gel can be dried and measured by
observation using a scanning electron microscope (SEM).
[0028]
The content of the barium titanate particles may be appropriately determined in consideration of
the dielectric constant, volume resistivity, flexibility and the like of the dielectric film. For
05-05-2019
9
example, the content of the barium titanate particles may be 10 parts by mass or more and 500
parts by mass or less with respect to 100 parts by mass of the elastomer. When the content of
the barium titanate particles is less than 10 parts by mass, the effect of increasing the relative
dielectric constant and the volume resistivity is small. On the other hand, if it exceeds 500 parts
by mass, the modulus of elasticity increases and the flexibility is impaired.
[0029]
As described above, the higher the crystallinity of barium titanate, the larger the relative
dielectric constant and the volume resistivity. As a method for producing barium titanate, a solid
phase reaction method, a hydrothermal synthesis method and a sol-gel method are known.
Among them, according to the solid phase reaction method, although the one having high
crystallinity can be obtained, the particles are easily aggregated by firing at high temperature.
For this reason, even if the particles after firing are crushed, only particles having a large particle
diameter can be obtained. If the particle size of barium titanate is large, it is difficult to uniformly
disperse it throughout the elastomer. In addition, when particles having a large particle size are
present, the elongation of the dielectric film at the time of voltage application tends to be
nonuniform. In this case, defects are likely to occur from the particles as a base point, and the
resistance to dielectric breakdown may be reduced. In addition, the functional groups on the
particle surface are reduced by firing. If the particle surface has few functional groups, it is
difficult to bond to the elastomer. For this reason, a crosslinked structure can not be formed by
the elastomer and the barium titanate particles.
[0030]
On the other hand, according to the usual hydrothermal synthesis method or the usual sol-gel
method, since the hydroxyl group etc. remain inside the particles, only particles with low
crystallinity can be obtained. Although the obtained particles can be fired to improve the
crystallinity, as in the case of the solid phase reaction method, there is a problem that the particle
diameter increases and the functional group on the particle surface decreases.
[0031]
Therefore, the barium titanate particles to be blended in the dielectric film of the present
invention can be prepared by the hydrothermal synthesis method using supercritical water
disclosed in Japanese Patent No. 3925932 or the high concentration precursor disclosed in It is
desirable to be manufactured by the sol-gel method used.
05-05-2019
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[0032]
For example, according to a hydrothermal synthesis method using supercritical water, barium
titanate particles are produced by supplying a metal complex containing barium and titanium in
a reaction environment in the supercritical water state for a predetermined time .
According to this method, barium titanate particles having a crystallinity of 80% or more and a
particle diameter of 120 nm or less can be easily produced.
[0033]
As the metal complex of the raw material, a single metal alkoxide or hydroxide containing barium
or titanium may be used in combination of plural kinds so as to become the composition of the
perovskite compound, and a complex alkoxide containing both barium and titanium You may use
For example, as barium alkoxide, barium methoxide, barium ethoxide, barium propoxide, barium
butoxide and the like can be mentioned. Moreover, titanium methoxide, titanium ethoxide,
titanium propoxide, titanium butoxide etc. are mentioned as a titanium alkoxide. Moreover,
barium titanium methoxide, barium titanium ethoxide, barium titanium propoxide, barium
titanium butoxide etc. are mentioned as complex alkoxide.
[0034]
Also, according to the sol-gel method using a high concentration precursor, barium titanate
particles have a concentration of a polar organic solvent of 15 mol% in a precursor solution
having a concentration of an alkoxide containing barium and titanium of 0.5 mol / l or more. A
mixed solution of the above water and a polar organic solvent is dropped so that the molar ratio
of the water in the mixed solution is 4 or more times the molar ratio of the titanium in the
precursor solution, and the alkoxide is After hydrolysis, it is produced by holding at a
temperature of 10 ° C. or higher. According to this method, barium titanate particles having a
crystallinity of 80% or more and a particle diameter of 120 nm or less can be easily produced.
[0035]
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11
As the raw material alkoxide, a single metal alkoxide containing barium or titanium may be used
in combination of two or more types to form the composition of the perovskite compound, and
even if a complex alkoxide containing both barium and titanium is used. Good. For example, as
barium alkoxide, barium methoxide, barium ethoxide, barium propoxide, barium butoxide and the
like can be mentioned. Moreover, titanium methoxide, titanium ethoxide, titanium propoxide,
titanium butoxide etc. are mentioned as a titanium alkoxide. Moreover, barium titanium
methoxide, barium titanium ethoxide, barium titanium propoxide, barium titanium butoxide etc.
are mentioned as complex alkoxide.
[0036]
An alkoxide containing barium and titanium is dissolved in, for example, a mixed solvent of
methanol and 2-methoxyethanol (3: 2 in volume ratio) or the like to prepare a precursor solution
having an alkoxide concentration of 0.5 mol / l or more. The solvent may be any solvent which
can dissolve alkoxide at a concentration of 0.5 mol / l or more, and alcohol solvents such as
methanol and ethanol, and ketone solvents such as methyl ethyl ketone and acetone may be used
alone or in combination. Good.
[0037]
As a polar organic solvent of the mixed solution dropped to the precursor solution, an alcoholbased, ketone-based or ether-based solvent may be used. In addition, in order to suppress rapid
hydrolysis and polycondensation reaction, it is preferable to drop the mixed solution while the
precursor solution is cooled to about -30 ° C. Then, the solution after hydrolysis is heated to 10
° C. or higher, and kept at this temperature for a predetermined time (aging treatment). The
holding temperature is preferably 30 ° C. or more. By performing the aging treatment, it is
possible to reduce the hydroxyl groups and the like remaining in the inside of the particles and to
improve the crystallinity. When the solution after hydrolysis is irradiated with ultrasonic waves
during the aging treatment, the crystallization reaction of the barium titanate particles is
promoted. Thereby, the time of the aging process can be shortened.
[0038]
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12
[Other Components] The dielectric film of the present invention may contain other components
in addition to the elastomer and the barium titanate particles. Other components include
crosslinking agents, reinforcing agents, plasticizers, antiaging agents, coloring agents and the
like. In the dielectric film of the present invention, a cross-linked structure is formed by the
reaction of the functional group of the barium titanate particle and the functional group of the
elastomer, even if the cross-linking agent is not blended. However, the addition of a crosslinking
agent can further accelerate the crosslinking reaction.
[0039]
<Method of Manufacturing Dielectric Film> The method of manufacturing the dielectric film of
the present invention is not particularly limited. For example, a polymer before crosslinking of an
elastomer, a barium titanate powder, and, if necessary, an additive may be kneaded using a roll
or a kneader to form a thin film under predetermined conditions. Alternatively, a solution
containing an elastomeric pre-crosslinking polymer, barium titanate powder, and, optionally,
additives may be applied onto a substrate and cured under predetermined conditions.
Alternatively, a dispersion of barium titanate particles may be used, in which a gel produced by
the sol-gel method using a high concentration precursor instead of barium titanate powder is
dispersed in a solvent.
[0040]
Transducer The transducer of the present invention comprises the dielectric film of the present
invention and a plurality of electrodes disposed via the dielectric film. The configuration of the
dielectric film of the present invention and the method for producing the same are as described
above. Therefore, the explanation is omitted here. Also in the transducer of the present invention,
it is desirable to adopt the preferred embodiment of the dielectric film of the present invention.
[0041]
The thickness of the dielectric film may be appropriately determined in accordance with the
application and the like. For example, in the case of using the transducer of the present invention
as an actuator, it is desirable that the dielectric film has a small thickness in terms of downsizing
of the actuator, low potential drive, and large displacement. In this case, it is desirable to set the
thickness of the dielectric film to 1 μm or more and 1000 μm (1 mm) or less in consideration
05-05-2019
13
of the dielectric breakdown resistance and the like. A more preferable range is 5 μm or more
and 200 μm or less.
[0042]
In the transducer of the present invention, the material of the electrode is not particularly limited.
It is desirable that the electrode be able to expand and contract following the deformation of the
dielectric film. In this case, deformation of the dielectric film is less likely to be regulated by the
electrodes. Therefore, in the transducer of the present invention, it becomes easy to obtain the
desired output. For example, the electrode can be formed of a conductive paste obtained by
mixing a conductive material with a binder such as oil or elastomer, or a conductive paint. As the
conductive material, carbon materials such as carbon black, ketjen black, carbon nanotubes, and
graphene, and metal powders such as silver may be used. Alternatively, the electrodes may be
formed by knitting carbon fibers or metal fibers in a mesh shape.
[0043]
Further, when the transducer of the present invention has a laminated structure in which a
plurality of dielectric films and electrodes are alternately laminated, a larger force can be
generated. Therefore, when the laminated structure is adopted, for example, the output of the
actuator can be increased. Thus, the drive target member can be driven with a larger force.
[0044]
Hereinafter, an embodiment in which the transducer of the present invention is embodied in an
actuator and a speaker will be described.
[0045]
First Embodiment An embodiment of an actuator will be described as a first embodiment of the
transducer of the present invention.
FIG. 1 shows a schematic cross-sectional view of the actuator of the present embodiment. (A)
shows a voltage off state, and (b) shows a voltage on state.
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[0046]
As shown in FIG. 1, the actuator 1 includes a dielectric film 10, electrodes 11a and 11b, and
wirings 12a and 12b. The dielectric film 10 has a carboxyl group-modified hydrogenated nitrile
rubber (HX-NBR) and barium titanate particles. The crystallinity of the barium titanate particles
is 95% and the median diameter is 20 nm. A crosslinked structure is formed by HX-NBR and
barium titanate particles. Barium titanate particles are uniformly dispersed in HX-NBR. The
electrode 11 a is arranged to cover substantially the entire top surface of the dielectric film 10.
Similarly, the electrode 11 b is disposed so as to cover substantially the entire lower surface of
the dielectric film 10. The electrodes 11a and 11b are connected to the power supply 13 through
the wirings 12a and 12b, respectively.
[0047]
When switching from the off state to the on state, a voltage is applied between the pair of
electrodes 11a and 11b. By the application of the voltage, the thickness of the dielectric film 10
is reduced, and by that amount, the dielectric film 10 extends in a parallel direction to the
surfaces of the electrodes 11a and 11b as shown by white arrows in FIG. 1 (b). Thereby, the
actuator 1 outputs the driving force in the vertical and horizontal directions in the drawing.
[0048]
In the dielectric film 10 of the present embodiment, the flow of electrons is blocked by the
insulating network formed of HX-NBR and barium titanate particles. In addition, the crystallinity
of the barium titanate particles is high. Therefore, the dielectric constant and the volume
resistivity of the dielectric film 10 are large. Therefore, when a voltage is applied to the dielectric
film 10, a large electrostatic attraction is generated. Therefore, according to the actuator 1, it is
possible to obtain a large force and a displacement amount by a practical voltage. Further, since
the dielectric film 10 has high resistance to dielectric breakdown, a larger voltage can be applied
to obtain a larger force and displacement.
[0049]
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Second Embodiment An embodiment of a loudspeaker will be described as a second embodiment
of the transducer of the present invention. First, the configuration of the speaker according to the
present embodiment will be described. FIG. 4 shows a perspective view of the speaker of the
present embodiment. FIG. 5 shows a V-V cross-sectional view of FIG. As shown in FIGS. 4 and 5,
the speaker 4 includes a first outer frame 40a, a first inner frame 41a, a first dielectric film 42a,
a first outer electrode 43a, a first inner electrode 44a, and One diaphragm 45a, second outer
frame 40b, second inner frame 41b, second dielectric film 42b, second outer electrode 43b,
second inner electrode 44b, second diaphragm 45b, eight A bolt 460, eight nuts 461, and eight
spacers 462 are provided.
[0050]
Each of the first outer frame 40 a and the first inner frame 41 a is made of resin and has a ring
shape. The first dielectric film 42a has a circular thin film shape. The first dielectric film 42a is
stretched between the first outer frame 40a and the first inner frame 41a. That is, the first
dielectric film 42a is held and fixed by the first outer frame 40a on the front side and the first
inner frame 41a on the back side in a state where a predetermined tension is secured. The first
dielectric film 42a has HX-NBR and barium titanate particles. The crystallinity of the barium
titanate particles is 95% and the median diameter is 20 nm. A crosslinked structure is formed by
HX-NBR and barium titanate particles. Barium titanate particles are uniformly dispersed in HXNBR. The first diaphragm 45a is made of resin and has a disk shape. The first diaphragm 45a is
smaller in diameter than the first dielectric film 42a. The first diaphragm 45a is disposed
substantially at the center of the surface of the first dielectric film 42a.
[0051]
The first outer electrode 43a has a ring shape. The first outer electrode 43a is attached to the
surface of the first dielectric film 42a. The first inner electrode 44a also has a ring shape. The
first inner electrode 44a is attached to the back surface of the first dielectric film 42a. The first
outer electrode 43a and the first inner electrode 44a face in the front and back direction with the
first dielectric film 42a interposed therebetween. The first outer electrode 43a and the first inner
electrode 44a are both formed of a conductive paint prepared by mixing and dispersing carbon
black in an acrylic rubber polymer solution. Moreover, as shown in FIG. 5, the 1st outer electrode
43a is provided with the terminal 430a. The first inner electrode 44a includes a terminal 440a.
An external voltage is applied to the terminals 430a and 440a.
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[0052]
The second outer frame 40b, the second inner frame 41b, the second dielectric film 42b, the
second outer electrode 43b, the second inner electrode 44b, and the second diaphragm 45b
(hereinafter, collectively referred to as "second members"). The first outer frame 40a, the first
inner frame 41a, the first dielectric film 42a, the first outer electrode 43a, the first inner
electrode 44a, the first diaphragm 45a (hereinafter referred to as “the first outer frame 40a, the
first inner frame Collectively referred to as "one member". Is the same as the configuration, the
material, and the shape. Further, the arrangement of the second member is symmetrical to the
arrangement of the first member in the front and back direction. Briefly explaining, the second
dielectric film 42b has a circular thin film shape, and is stretched between the second outer
frame 40b and the second inner frame 41b. The second dielectric film 42 b includes HX-NBR and
barium titanate particles. The second diaphragm 45b is disposed substantially at the center of
the surface of the second dielectric film 42b. The second outer electrode 43b is attached to the
surface of the second dielectric film 42b. The second inner electrode 44b is attached to the back
surface of the second dielectric film 42b. A voltage is applied from the outside to the terminal
430 b of the second outer electrode 43 b and the terminal 440 b of the second inner electrode
44 b.
[0053]
The first member and the second member are fixed by eight bolts 460 and eight nuts 461 via
eight spacers 462. The sets of “bolts 460-nuts 461-spacers 462” are arranged at
predetermined intervals in the circumferential direction of the speaker 4. The bolt 460
penetrates from the surface of the first outer frame 40a to the surface of the second outer frame
40b. The nut 461 is screwed to the through end of the bolt 460. The spacer 462 is made of resin
and is annularly mounted on the shaft portion of the bolt 460. The spacer 462 secures a
predetermined interval between the first inner frame 41a and the second inner frame 41b. The
back surface of the central portion of the first dielectric film 42a (the back side of the portion
where the first diaphragm 45a is disposed) and the back surface of the center portion of the
second dielectric film 42b (the back side of the portion where the second diaphragm 45b is
disposed) And are joined. Therefore, a biasing force is accumulated in the first dielectric film 42a
in the direction indicated by the white arrow Y1a in FIG. Further, a biasing force is accumulated
in the second dielectric film 42b in the direction indicated by the white arrow Y1b in FIG.
[0054]
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Next, the movement of the speaker of this embodiment will be described. The first outer
electrode 43a and the first inner electrode 44a, and the second outer electrode 43b and the
second inner electrode 44b in the initial state (offset state) through the terminals 430a and 440a
and the terminals 430b and 440b. , And a predetermined voltage (offset voltage) is applied.
When the speaker 4 is in operation, voltages of opposite phase are applied to the terminals 430a
and 440a and the terminals 430b and 440b. For example, when offset voltage +1 V is applied to
the terminals 430a and 440a, the film thickness of the portion of the first dielectric film 42a
disposed between the first outer electrode 43a and the first inner electrode 44a is thin. Become.
And the portion extends radially. At the same time, reverse phase voltage (offset voltage -1 V) is
applied to the terminals 430b and 440b. Then, in the second dielectric film 42b, the film
thickness of the portion disposed between the second outer electrode 43b and the second inner
electrode 44b is increased. And the portion shrinks in the radial direction. Thereby, the second
dielectric film 42b is elastically deformed by its own biasing force in the direction shown by the
white arrow Y1b in FIG. 5 while pulling the first dielectric film 42a. On the other hand, when the
offset voltage +1 V is applied to the terminals 430 b and 440 b and a voltage (offset voltage -1 V)
of opposite phase is applied to the terminals 430 a and 440 a, the first dielectric film 42 a pulls
the second dielectric film 42 b. While being elastically deformed by its own biasing force in the
direction shown by the white arrow Y1a in FIG. Thus, air is vibrated by vibrating the first
diaphragm 45a and the second diaphragm 45b to generate sound.
[0055]
Next, the operation and effect of the speaker 4 of the present embodiment will be described.
According to this embodiment, the relative dielectric constants of the first dielectric film 42 a and
the second dielectric film 42 b are large. For this reason, the electrostatic attraction with respect
to an applied voltage becomes large. Also, the volume resistivity of the first dielectric film 42 a
and the second dielectric film 42 b is large. Therefore, many charges can be accumulated near
the interface between the first dielectric film 42a and the first outer electrode 43a and the first
inner electrode 44a. Similarly, many charges can be accumulated near the interface between the
second dielectric film 42b and the second outer electrode 43b and the second inner electrode
44b. As a result, the displacement amounts of the first dielectric film 42a and the second
dielectric film 42b become large, and the first diaphragm 45a and the second diaphragm 45b can
be vibrated with a large amplitude. Therefore, the sound pressure of the speaker 4 is increased.
[0056]
Next, the present invention will be more specifically described by way of examples.
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[0057]
<Production of dielectric film> [Example 1] First, a carboxyl group-modified hydrogenated nitrile
rubber ("Terban (registered trademark) XT 8889" manufactured by LANXCESS Co., Ltd.) is
dissolved in acetylacetone to form a polymer having a solid content concentration of 12% by
mass. The solution was prepared.
Next, a dispersion of barium titanate particles was prepared in 100 parts by mass of the
prepared polymer solution. 120 parts by mass were mixed to prepare a mixed solution. Then, the
prepared mixed solution was applied onto a substrate, dried, and heated at 150 ° C. for about
60 minutes to obtain a dielectric film. The film thickness of the dielectric film was about 20 μm,
and the content of the barium titanate particles was 120 parts by mass with respect to 100 parts
by mass of the elastomer (HX-NBR). The manufactured dielectric film was used as the dielectric
film of Example 1.
[0058]
Comparative Example 1 A dielectric film made of HX-NBR was manufactured in the same manner
as in Example 1 except that the dispersion liquid of barium titanate particles was not blended.
The manufactured dielectric film was used as the dielectric film of Comparative Example 1.
[0059]
Example 2 A dielectric film was produced in the same manner as in Example 1 except that a
crosslinking agent was added and the amount of the dispersion of barium titanate particles was
reduced. That is, 53 parts by mass of a dispersion liquid of barium titanate particles (same as
above) is mixed with 100 parts by mass of a polymer solution in which carboxyl group-modified
hydrogenated nitrile rubber (same as above) is dissolved in acetylacetone. A mixed solution was
prepared by adding 5 parts by mass of an acetylacetone solution of ethylhexyloxy) titanium
(concentration 20% by mass). Then, the prepared mixed solution was applied onto a substrate,
dried, and heated at 150 ° C. for about 60 minutes to obtain a dielectric film. The film thickness
of the dielectric film was about 20 μm, and the content of the barium titanate particles was 53
parts by mass with respect to 100 parts by mass of the elastomer (HX-NBR). The manufactured
05-05-2019
19
dielectric film was used as the dielectric film of Example 2.
[0060]
Comparative Example 2 Barium titanate powder A (manufactured by Kyoritsu Material Co., Ltd.
“BT-150”, crystallinity 95%, instead of the dispersion liquid of barium titanate particles,
manufactured by a usual hydrothermal synthesis method A dielectric film was produced in the
same manner as in Example 2 except that the average particle size was 150 nm. The content of
barium titanate particles was 53 parts by mass with respect to 100 parts by mass of the
elastomer (HX-NBR). The manufactured dielectric film was used as the dielectric film of
Comparative Example 2.
[0061]
Example 3 The same procedure as in Example 1 was repeated, except that 53 parts by mass of
barium titanate powder B produced by the following hydrothermal synthesis method using
supercritical water was used instead of the dispersion liquid of barium titanate particles. The
dielectric film was manufactured. The content of barium titanate particles was 53 parts by mass
with respect to 100 parts by mass of the elastomer (HX-NBR). The manufactured dielectric film
was used as the dielectric film of Example 3.
[0062]
0.12 mol / l of a barium hydroxide solution and 0.1 mol / l of a titanium oxide solution ("STS-01"
manufactured by Ishihara Sangyo Co., Ltd.) using a flow-through type supercritical hydrothermal
synthesis apparatus (manufactured by ITEC Co., Ltd.) and l were mixed with water in the
supercritical state and reacted for 0.5 seconds. Thus, barium titanate powder B having a median
diameter of 12 nm and a crystallinity of 98% was produced.
[0063]
[Example 4] In the hydrothermal synthesis method with supercritical water of Example 3, barium
titanate powder C was manufactured with the reaction time with water in the supercritical state
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being 2 seconds. The median diameter of barium titanate powder C was 60 nm, and the degree of
crystallinity was 98%. Then, a dielectric film was manufactured in the same manner as in
Example 1, except that 53 parts by mass of barium titanate powder C was blended instead of the
dispersion liquid of barium titanate particles. The content of barium titanate particles was 53
parts by mass with respect to 100 parts by mass of the elastomer (HX-NBR). The manufactured
dielectric film was used as the dielectric film of Example 4.
[0064]
Example 5 A dielectric film is manufactured in the same manner as Example 3, except that 5
parts by mass of a solution of tetrakis (2-ethylhexyloxy) titanium in acetylacetone (concentration
20 mass%) is added as a crosslinking agent. did. The manufactured dielectric film was used as the
dielectric film of Example 5.
[0065]
Example 6 A dielectric film is manufactured in the same manner as Example 4, except that 5
parts by mass of a solution of tetrakis (2-ethylhexyloxy) titanium in acetylacetone (concentration
20 mass%) is added as a crosslinking agent. did. The manufactured dielectric film was used as the
dielectric film of Example 6.
[0066]
<Physical Properties of Dielectric Film> [Volume Resistivity] The volume resistivity of the
manufactured dielectric film was measured according to JIS K6271 (2008). The measurement
was performed by applying a DC voltage of 100V.
[0067]
[Specific Permittivity] The relative permittivity of the manufactured dielectric film was measured.
To measure the relative permittivity, place the dielectric film on the sample holder (Solatron,
model 12962A), measure the permittivity measurement interface (Sorry, model 1296), and the
frequency response analyzer (Sorry, model 1255B) It carried out together (frequency 100Hz).
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[0068]
[Elastic Modulus] The static shear modulus of the manufactured dielectric film was measured
according to JIS K 6254 (2003). The elongation percentage in the low deformation tensile test
was 25%.
[0069]
Elongation at break The elongation at break of the manufactured dielectric film was measured
according to JIS K 6251 (2010). The shape of the test piece was a dumbbell shape No. 5.
[0070]
[Crosslinkability] First, a test piece for evaluation was cut out from the manufactured dielectric
film, and the mass of the test piece was measured. Next, the test piece was immersed in methyl
ethyl ketone (MEK) for 4 hours at room temperature. Thereafter, the test piece was taken out,
dried and weighed. And the mass ratio (MEK insoluble matter) after immersion to the mass
before immersion of a test piece is calculated, and if it is 60% or more, the crosslinkability is
good (indicated by ○ in Table 1 below), if it is less than 60% It was evaluated that the
crosslinkability was poor (indicated by x in the same table).
[0071]
[Evaluation] Various measurement results of the dielectric film are shown in Table 1 together
with the raw material composition.
[0072]
In Table 1, first, Examples 1, 3 and 4 in which no crosslinking agent was blended, and
Comparative Example 1 are compared.
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In the dielectric films of Examples 1, 3 and 4, the dielectric constant and the elastic modulus
were larger than those of the dielectric film of Comparative Example 1, and the volume resistivity
was also increased by about two digits. Further, in the dielectric film of Comparative Example 1,
the crosslinking did not proceed, but the crosslinkability of the dielectric films of Examples 1, 3
and 4 was good. In the dielectric films of Examples 1, 3 and 4, the elongation at break was also
significantly improved. That is, in the dielectric films of Examples 1, 3 and 4, it can be seen that a
crosslinked structure is formed by the barium titanate particles and the elastomer.
[0073]
Next, Examples 2, 5 and 6 containing a crosslinking agent are compared with Comparative
Example 2. Although both of them have barium titanate particles, in Examples 2 and 6, all of
volume resistivity, relative dielectric constant, elastic modulus, and elongation at break increased
compared to the dielectric film of Comparative Example 2. In the dielectric film of Example 5,
compared with the dielectric film of Comparative Example 2, the volume resistivity, the elastic
modulus, and the elongation at break became larger except for the relative dielectric constant.
Incidentally, the dielectric constant of the dielectric film of Example 5 was larger than the
dielectric constant of the dielectric film of Comparative Example 1 which did not contain barium
titanate particles. In the dielectric film of Example 5, the particle diameter of the blended barium
titanate particles was small, so the effect of increasing the relative dielectric constant was small.
However, if the particle size is small, a dense insulating network is formed, and the effect of
increasing the volume resistivity is large. Therefore, the particle diameter of the barium titanate
particles may be appropriately determined so as to obtain desired characteristics.
[0074]
The barium titanate particles blended in the dielectric film of Comparative Example 2 are fired
after synthesis. For this reason, the degree of crystallinity is considered to be high, but the
number of functional groups on the particle surface is small. In addition, the particle size is also
large. Therefore, even when such titanium barium particles are blended, the effect of increasing
the volume resistivity and the relative dielectric constant is small. The crosslinkability of the
dielectric film of Comparative Example 2 was good. This is because a crosslinked structure was
formed by the blended crosslinking agent.
[0075]
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<Manufacture of Actuator> An actuator was manufactured using the manufactured dielectric
film. First, carbon black was mixed and dispersed in an acrylic rubber polymer solution to
prepare a conductive paint. Next, a conductive paint was screen-printed on both sides of the
manufactured dielectric film to form electrodes. The actuator manufactured in this manner is
referred to as "the actuator of Example 1" or the like, corresponding to the type of dielectric film.
In addition, a cation fixed dielectric layer was adhered to the surface of the dielectric film of
Example 6, and an anion fixed dielectric layer was adhered to the back surface, to prepare a
three-layered dielectric layer. An actuator was manufactured in the same manner as described
above using the manufactured three-layered dielectric layer. The manufactured actuator is
referred to as the actuator of Example 7. The actuators of Examples 1 to 7 are included in the
transducer of the present invention. The cation fixed dielectric layer and the anion fixed dielectric
layer were produced as follows.
[0076]
[Positive Ion Fixed Dielectric Layer] A positive ion fixed dielectric layer was prepared as follows.
First, 0.02 mol of acetylacetone was added to 0.01 mol of tetra-i-propoxytitanium as an
organometallic compound to conduct chelate formation. Next, 0.002 mol of a reactive ionic liquid
represented by the following formula (2), 5 ml (0.083 mol) of isopropyl alcohol (IPA), 10 ml
(0.139 mol) of methyl ethyl ketone (MEK), and 0.04 mol of water was added to obtain a cationimmobilized TiO 2 particle (cation-immobilized particles) and a sol containing anions. Then, the
obtained sol was left to stand at 40 ° C. for 2 hours for aging treatment.
[0077]
Next, 100 parts by mass of a carboxyl group-modified hydrogenated nitrile rubber ("Terban
(registered trademark) XT 8889" manufactured by Lanxess Co., Ltd.) and 10 parts by mass of
silica ("Aerosil (registered trademark) 380" manufactured by Nippon Aerosil Co., Ltd.) Were
kneaded using a roll mill. Then, the kneaded material was dissolved in acetylacetone. 100 parts
by mass of this solution and 20 parts by mass of the sol after aging are mixed, and 3 parts by
mass of an acetylacetone solution (concentration 20 mass%) of tetrakis (2-ethylhexyloxy)
titanium is further added as a crosslinking agent, A mixture was prepared. Then, the prepared
mixed solution was applied onto a substrate, dried, and then heated at 150 ° C. for about 60
minutes to obtain a cation fixed dielectric layer. The thickness of the cation fixed dielectric layer
was about 10 μm, and the content of the cation fixed particles was 6.6 parts by mass. <img class
= "EMIRef" id = "280709502-00004" />
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[0078]
[Anion Fixing Dielectric Layer] An anion fixing dielectric with a thickness of about 10 μm is
prepared in the same manner as the cation fixing dielectric layer except that the type of reactive
ionic liquid is changed to that shown in the following formula (3). The layers were made. The sol
obtained in the preparation process contains TiO 2 particles (anion fixed particles) to which an
anion is fixed, and a cation. <img class = "EMIRef" id = "280709502-00005" />
[0079]
<Evaluation of Actuator> The dielectric breakdown strength and the maximum generated stress
were measured for the manufactured actuator. First, the measuring apparatus and the measuring
method will be described. FIG. 2 shows a front side front view of an actuator attached to the
measuring device. In FIG. 3, III-III sectional drawing of FIG. 2 is shown.
[0080]
As shown in FIGS. 2 and 3, the upper end of the actuator 5 is gripped by the upper chuck 52 in
the measuring device. The lower end of the actuator 5 is gripped by the lower chuck 53. The
actuator 5 is attached between the upper chuck 52 and the lower chuck 53 in a state of being
stretched in the vertical direction in advance (stretching ratio 25%). A load cell (not shown) is
disposed above the upper chuck 52.
[0081]
The actuator 5 is composed of a dielectric film 50 and a pair of electrodes 51a and 51b. The
dielectric film 50 is in the form of a rectangular thin film having a length of 50 mm, a width of
25 mm, and a thickness of about 20 μm in a natural state. In the actuator of Example 7, the
dielectric film 50 has a three-layer structure of positive ion fixed dielectric layer / dielectric film /
negative ion fixed dielectric layer (total thickness 40 μm). The electrodes 51 a and 51 b are
disposed to face each other in the front and back direction with the dielectric film 50 interposed
therebetween. The electrodes 51a and 51b each have a rectangular thin film shape of 40 mm
05-05-2019
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long, 25 mm wide, and 10 μm thick in a natural state. The electrodes 51a and 51b are arranged
in a state of being offset by 10 mm in the vertical direction. That is, the electrodes 51 a and 51 b
overlap each other in the range of 30 mm long and 25 mm wide via the dielectric film 50. A wire
(not shown) is connected to the lower end of the electrode 51a. Similarly, a wire (not shown) is
connected to the upper end of the electrode 51b. The electrodes 51a and 51b are connected to a
power supply (not shown) via the respective wirings.
[0082]
When a voltage is applied between the electrodes 51a and 51b, an electrostatic attractive force is
generated between the electrodes 51a and 51b to compress the dielectric film 50. As a result, the
thickness of the dielectric film 50 becomes thinner and extends in the stretching direction
(vertical direction). The stretching of the dielectric film 50 reduces the stretching force in the
vertical direction. The stretching force reduced before and after the application of voltage was
measured by the load cell and used as the generated stress. The measurement of the generated
stress was performed by gradually increasing the applied voltage until the dielectric film 50 was
broken. Then, the generated stress immediately before the dielectric film 50 is broken is taken as
the maximum generated stress. Further, the value obtained by dividing the voltage value at that
time by the film thickness of dielectric film 50 (the total thickness of the cation fixed dielectric
layer / dielectric film / anion fixed dielectric layer in the actuator of Example 7) is the dielectric
breakdown strength And Table 1 collectively shows the measurement results of the dielectric
breakdown strength and the maximum generated stress in the actuators of Examples 1 to 6 and
Comparative Examples 1 and 2.
[0083]
In Table 1, first, Examples 1, 3, 4 and Comparative Example 1 are compared. In the actuators of
Examples 1, 3 and 4, the dielectric breakdown strength and the maximum generated stress were
significantly increased as compared with the actuator of Comparative Example 1. Next, Examples
2, 5, 6 and Comparative Example 2 are compared. Also in this case, the breakdown strength and
the maximum generated stress of the actuators of Examples 2, 5 and 6 were significantly larger
than that of the actuator of Comparative Example 2. The dielectric film which comprises the
actuator of Example 1, 2 is manufactured by the sol gel process using a high concentration
precursor, and contains barium titanate particle | grains whose crystallinity degree is 95%. The
dielectric film which comprises the actuator of Examples 3-6 is manufactured by the
hydrothermal synthesis method by supercritical water, and contains the barium titanate particle
whose crystallinity degree is 98%. These titanium barium particles have functional groups (-OH, -
05-05-2019
26
OR) that can react with functional groups (-COOH) of HX-NBR. Therefore, regardless of the
presence or absence of the crosslinking agent, a crosslinked structure was formed by the
elastomer and the barium titanate particles, and the dielectric breakdown strength of the
dielectric film was significantly improved. On the other hand, it is considered that the surface of
the barium titanate particles blended in the dielectric film of Comparative Example 2 has few
functional groups capable of reacting with the functional group of HX-NBR. Therefore, although
the crosslinking proceeded by the blended crosslinking agent, an insulating network was not
formed due to the bonding of the barium titanate particles and the elastomer, and the dielectric
breakdown strength of the dielectric film was not improved.
[0084]
In addition, the dielectric breakdown strength of the actuator of Example 7 in which the cation
fixed dielectric layer and the anion fixed dielectric layer were laminated with the dielectric film of
Example 6 interposed therebetween was 100 V / μm, and the maximum generated stress was
2.01 MPa. Thus, it is confirmed that when the ion fixing dielectric layer is interposed between the
electrode and the dielectric film, the dielectric breakdown resistance of the dielectric film can be
sufficiently exhibited, and the dielectric breakdown resistance of the actuator is improved. It was
done. Moreover, it was confirmed that the generated stress also becomes larger.
[0085]
From the above, it has been confirmed that by using the dielectric film of the present invention,
an actuator having high resistance to dielectric breakdown and capable of outputting a large
force can be realized.
[0086]
The transducer using the dielectric film of the present invention can be widely used as an
actuator, sensor or the like for converting between mechanical energy and electric energy, or as a
speaker, microphone, noise canceler, etc. for converting between acoustic energy and electric
energy. .
Among them, it is suitable as an artificial muscle used for industry, medicine, welfare robot, assist
suit, etc., a small pump for cooling electronic parts, for medical use, etc., and a flexible actuator
used for medical instruments etc.
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