JP2008243897A - Acrylic rubber for electrostriction type actuator and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic rubber of high dielectric ratio which provides a large displacement amount at a low voltage when used for an electrostriction type actuator, and to provide a method of manufacturing the acrylic rubber by shortening bridging time. <P>SOLUTION: The acrylic rubber for an electrostriction type actuator is obtained by bridging acrylic ester polymer containing epoxy group with ionic photoacid generating agent. The manufacturing method of acrylic rubber for an electrostriction type actuator includes an acrylic rubber composition preparing process for preparing the acrylic rubber composition containing acrylic ester polymer containing epoxy group and ionic photoacid generating agent, and a bridging process for bridging by radiating light to the acrylic rubber composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an acrylic rubber used for an electrostrictive actuator and a method for producing the same.

In the fields of industrial and nursing robots, medical equipment, micromachines, and the like, there is an increasing need for highly flexible, small, and lightweight actuators. As such an actuator material, for example, various polymers such as a conductive polymer, an ion conductive polymer (ICPF), and a dielectric elastomer have been proposed. In particular, an electrostrictive actuator using a dielectric elastomer is useful because it can be easily miniaturized and manufactured at low cost. For example, Patent Documents 1 and 2 introduce electrostrictive actuators in which a dielectric elastomer film is held between a pair of electrodes.
Special table 2003-506858 JP 2005-323482 A

  In the electrostrictive actuator, when the voltage applied between the electrodes is increased, the electrostatic attractive force between the electrodes is increased. Therefore, the dielectric elastomer film sandwiched between the electrodes is compressed from the film thickness direction, and the film thickness of the dielectric elastomer film is reduced. As the film thickness decreases, the dielectric elastomer film extends in a direction parallel to the electrode surface. Further, when the voltage applied between the electrodes is reduced, the electrostatic attractive force between the electrodes is reduced. For this reason, the compressive force from the film thickness direction to the dielectric elastomer film is reduced, and the film thickness is increased by the elastic restoring force of the dielectric elastomer film. As the film thickness increases, the dielectric elastomer film shrinks in the direction parallel to the electrode surface. The electrostrictive actuator outputs a driving force by extending and contracting (displacement) the dielectric elastomer film.

  Conventionally, acrylic rubber, silicone rubber, fluorine rubber and the like have been used as the dielectric elastomer film. However, for example, when a commercially available acrylic rubber is used, there is a problem that a sufficient amount of displacement cannot be obtained with respect to a predetermined applied voltage because the dielectric constant of the acrylic rubber is low.

  Moreover, when manufacturing acrylic rubber, the amine compound etc. are used as a crosslinking agent. Therefore, in order to crosslink an uncrosslinked acrylic rubber composition, it is necessary to hold the acrylic rubber composition for 30 minutes or more in a state where the acrylic rubber composition is heated to a predetermined temperature. Thus, according to the conventional manufacturing method, the time required for crosslinking is long. For this reason, productivity is low, for example, it is not suitable for the manufacturing process which laminates | stacks the thin film of an acrylic rubber and makes it a device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an acrylic rubber having a high dielectric constant and capable of obtaining a large displacement at a low voltage when used in an electrostrictive actuator. . Another object of the present invention is to provide a method capable of producing such an acrylic rubber with a reduced crosslinking time.

  (1) In order to solve the above problems, the acrylic rubber for electrostrictive actuators of the present invention crosslinks an acrylic rubber composition containing an epoxy group-containing acrylic ester polymer and an ionic photoacid generator. It is characterized by being obtained (corresponding to claim 1).

  The acrylic rubber composition in the present invention comprises an epoxy group-containing acrylic ester polymer as a main component and an ionic photoacid generator as a crosslinking agent. The epoxy group-containing acrylic ester polymer has an epoxy group serving as a crosslinking site in the side chain. The ionic photoacid generator is decomposed by light irradiation to generate an acid. The generated acid opens and crosslinks the epoxy group of the epoxy group-containing acrylic ester polymer.

  Thus, according to the ionic photoacid generator, the crosslinking reaction can proceed only by irradiating the acrylic rubber composition with light. For this reason, compared with the past, the crosslinking time can be greatly shortened. That is, the manufacturing time of the acrylic rubber for electrostrictive actuators of the present invention (hereinafter referred to as “the acrylic rubber of the present invention” as appropriate) can be greatly shortened. Thereby, the productivity of the acrylic rubber of the present invention is improved. Therefore, the acrylic rubber of the present invention is suitable for producing a laminated device by making a thin film.

  Moreover, an ionic photoacid generator consists of a cation part and an anion part, and has polarity. For this reason, only by adding a small amount, the polarity can be increased while maintaining the insulating property of the acrylic rubber of the present invention. This increases the dielectric constant of the acrylic rubber of the present invention. That is, in the acrylic rubber of the present invention, the ionic photoacid generator plays a role of increasing the dielectric constant in addition to the role as a crosslinking agent. Therefore, when an electrostrictive actuator is configured using the acrylic rubber of the present invention having a high dielectric constant, a larger displacement can be obtained when the same voltage as that in the conventional case is applied. In other words, the applied voltage can be lowered when it is desired to obtain a desired amount of displacement.

  (2) Moreover, the manufacturing method of the acrylic rubber for electrostrictive actuators of this invention is the acrylic rubber which prepares the acrylic rubber composition containing an epoxy-group-containing acrylic ester polymer and an ionic photo-acid generator. It has a composition preparation process, and the crosslinking process which irradiates light to the said acrylic rubber composition and bridge | crosslinks (corresponding to claim 4).

  According to the production method of the present invention, the acrylic rubber composition prepared in the acrylic rubber composition preparation step can be cross-linked by a simple technique of irradiating light in the cross-linking step. Thus, according to the production method of the present invention, the acrylic rubber of the present invention having a high dielectric constant can be produced simply and in a short time.

  Hereinafter, the acrylic rubber of the present invention and the production method thereof will be described in detail. An embodiment of an electrostrictive actuator using the acrylic rubber of the present invention will also be described.

<Acrylic rubber>
The acrylic rubber of the present invention is obtained by crosslinking an acrylic rubber composition containing an epoxy group-containing acrylic ester polymer and an ionic photoacid generator. The epoxy group-containing acrylate polymer that is the first component of the acrylic rubber composition may be an acrylate polymer that has an epoxy group as a crosslinking site. For example, an epoxy group-containing monomer, an acrylate ester monomer, and a monomer copolymerizable therewith if necessary are copolymerized by a known method such as emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, etc. And copolymers.

  Here, examples of the epoxy group-containing monomer include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methallyl glycidyl ether.

  Examples of the acrylic acid ester monomers include various acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, 2-methoxyethyl acrylate, Examples include various alkoxyalkyl esters of acrylic acid such as 2- (n-propoxy) ethyl acrylate, 2- (n-butoxy) ethyl acrylate, and 3-methoxypropyl acrylate.

  Furthermore, monomers that can be copolymerized as required include 1,1-dihydroperfluoroethyl (meth) acrylate, 1,1-dihydroperfluoropropyl (meth) acrylate, 1,1,5-trihydroperfluorohexyl (meth) ) Various fluorine-containing acrylic esters such as acrylates, various hydroxyl group-containing acrylic esters such as 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, and diethylaminoethyl (meth) ) Various tertiary amino group-containing acrylic esters such as acrylate and dibutylaminoethyl (meth) acrylate, and various methacrylates such as methyl methacrylate and octyl methacrylate, acrylonitrile, alkyl vinyl keto , Vinyl ethers, allyl ethers, vinyl aromatic compounds, vinyl nitriles, ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl acetate, vinyl propionate, alkyl fumarate, and the like.

  Examples of the epoxy group-containing acrylate polymer include commercially available products such as “NOXTITE (registered trademark)” manufactured by NOK, “NIPOL (registered trademark) AR” manufactured by Nippon Zeon, and manufactured by Toupe. "Toacron (registered trademark)", Denka (registered trademark) ER manufactured by Denki Kagaku Kogyo Co., Ltd., "RV Series" manufactured by Nissin Chemical Industry Co., Ltd., "Esprene (registered trademark) EMA" manufactured by Sumitomo Chemical Co., Ltd. Etc. can be used.

The ionic photoacid generator that is the second component of the acrylic rubber composition is a compound that has ionic properties and generates an acid upon irradiation with light. As an ionic photoacid generator, an onium salt comprising a cation moiety that absorbs irradiated light and an anion moiety that generates an acid is known. For example, the mechanism of acid generation in a sulfonium salt-based ionic photoacid generator is as follows. FIG. 1 shows an acid generation mechanism in a sulfonium salt-based ionic photoacid generator. As shown in FIG. 1 (a), an ionic photoacid generator, a cation that absorbs the irradiation light, the anion portion of an acid is produced and (X = PF _6, etc.), made of. When irradiated with light, the ionic photoacid generator is decomposed (b), and the hydrogen of the solvent or the ionic photoacid generator itself is extracted (c) to generate an acid (d). The generated acid coordinates to the epoxy group of the epoxy group-containing acrylic ester polymer. As a result, the epoxy group is opened and the crosslinking reaction proceeds.

As such an ionic photoacid generator, for example, the cation part is aromatic sulfonium, the anion part is BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , A sulfonium salt composed of [BA ₄ ] ⁻ (A is a phenyl group substituted with two or more fluorine or trifluoromethyl groups), etc., a cation part is aromatic iodonium, an anion part is BF ₄ ⁻ , PF ₆ ⁻ , SbF ^{_{6 -, CF 3 SO 3 -}} , C 4 F 9 SO 3 -, [BA 4] - (a is a phenyl group substituted with 2 or more fluorine or a trifluoromethyl group) iodonium salt comprising the like are suitable . Of these, sulfonium salts are preferred. Specifically, unsubstituted triarylsulfonium hexafluorophosphate, triarylsulfonium hexafluoroantimonate, triarylsulfonium trifluoromethanesulfonate, and triaryl substituted with a phenylthio group. Examples include reel sulfonium hexafluorophosphate, triarylsulfonium hexafluoroantimonate, and triarylsulfonium trifluoromethanesulfonate substituted with a methyl group. In particular, the anion portion is PF ₆ ^- is a sulfonium salt (unsubstituted triarylsulfonium hexafluorophosphate, triarylsulfonium substituted with phenylthio group hexafluorophosphate, etc.) crosslinking, stability, excellent in safety ing.

  The acrylic rubber composition may contain various additives in addition to the epoxy group-containing acrylic ester polymer and the ionic photoacid generator. Examples of the additive include a plasticizer, a filler, an anti-aging agent, a softening agent, and a coloring agent. The acrylic rubber composition may be prepared by kneading the constituent components. Moreover, you may prepare a component by disperse | distributing and melt | dissolving in a predetermined solvent. In this case, it is desirable to evaporate the solvent before crosslinking. In any case, the acrylic rubber before crosslinking containing each constituent component is referred to as an acrylic rubber composition.

  The acrylic rubber composition is crosslinked to obtain the acrylic rubber of the present invention. Here, the ionic photoacid generator acts as a crosslinking agent as described above. The method for producing the acrylic rubber of the present invention will be described later. The obtained acrylic rubber of the present invention has a crosslinked structure formed by ring opening of an epoxy group in the side chain of an epoxy group-containing acrylic ester polymer. The acrylic rubber of the present invention includes a decomposition product of an ionic photoacid generator.

  In the electrostrictive actuator, the relative dielectric constant of the acrylic rubber of the present invention is desirably 10 or more from the viewpoint of obtaining a large displacement at a low voltage. It is more preferable that it is 20 or more. The relative permittivity can be measured, for example, by placing an acrylic rubber sample to be measured in a sample holder (Solartron, model 12962A), a dielectric constant measurement interface (manufactured by the company, model 1296), and a frequency response analyzer (manufactured by the company, 1255B) may be used in combination. The value measured by the above apparatus is adopted as the value of the relative dielectric constant in the present specification.

<Method for producing acrylic rubber>
The method for producing an acrylic rubber for an electrostrictive actuator of the present invention includes an acrylic rubber composition preparation step and a crosslinking step. Hereinafter, each process will be described.

(1) Acrylic rubber composition preparation step In this step, an acrylic rubber composition containing an epoxy group-containing acrylic ester polymer and an ionic photoacid generator is prepared. Since the epoxy group-containing acrylic ester polymer and the ionic photoacid generator have been described in the above <Acrylic rubber>, description thereof is omitted here. Here, the blending amount of the ionic photoacid generator is 0.1 parts by weight or more with respect to 100 parts by weight of the epoxy group-containing acrylic ester polymer from the viewpoint of sufficiently proceeding the crosslinking reaction. desirable. It is more suitable when it is 0.5 parts by weight or more. On the other hand, from the viewpoint of ensuring insulation, the content is preferably 10 parts by weight or less. More preferably, it is 5 parts by weight or less.

  The acrylic rubber composition can be prepared, for example, as follows (first preparation method). First, an epoxy group-containing acrylic ester polymer is dissolved in a predetermined solvent. The solvent is not particularly limited as long as the epoxy group-containing acrylic ester polymer is dissolved, and examples thereof include methyl ethyl ketone (MEK), tetrahydrofuran (THF), ethyl acetate, butyl acetate, methyl isobutyl ketone (MIBK) and the like. Subsequently, an ionic photoacid generator and, if necessary, an additive are added to this solution, and the mixture is stirred and mixed to obtain an acrylic rubber composition.

  The acrylic rubber composition can also be prepared as follows (second preparation method). First, an additive is added to the epoxy group-containing acrylic ester polymer as necessary, and kneaded. Next, an ionic photoacid generator is added and further kneaded, and if necessary, molded into a predetermined shape to obtain an acrylic rubber composition.

(2) Crosslinking step In this step, the prepared acrylic rubber composition is irradiated with light for crosslinking. For example, when the first preparation method is employed, the prepared acrylic rubber composition is applied onto a base material such as polyethylene terephthalate (PET) and dried to evaporate the solvent. Thereafter, the acrylic rubber composition formed in a film shape may be put together with the substrate into a light irradiation device, and the acrylic rubber composition may be irradiated with light such as ultraviolet rays. In addition, when the second preparation method is adopted, the prepared acrylic rubber composition may be put in a light irradiation device, and the acrylic rubber composition may be irradiated with light such as ultraviolet rays. In any case, the light irradiation time may be about 5 seconds to 120 seconds.

<Electrostrictive actuator>
When an electrostrictive actuator is configured using the acrylic rubber of the present invention, for example, a dielectric film is formed by forming the acrylic rubber of the present invention into a thin film, and a pair of electrodes are arranged with the dielectric film interposed therebetween. That's fine. Hereinafter, an embodiment of an electrostrictive actuator using the acrylic rubber of the present invention will be described.

  FIG. 2 is a schematic cross-sectional view of an electrostrictive actuator using the acrylic rubber of the present invention. (A) shows an OFF state, and (b) shows an ON state. As shown in FIG. 2, the electrostrictive actuator 1 includes a dielectric film 20 and electrodes 21a and 21b. The dielectric film 20 is made of the acrylic rubber of the present invention. The electrodes 21a and 21b are fixed to the front and back of the dielectric film 20, respectively. The electrodes 21a and 21b are connected to the power source 22 through conductive wires. When switching from the off state to the on state, a voltage is applied between the pair of electrodes 21a and 21b. As a voltage is applied, the film thickness of the dielectric film 20 is reduced, and as much as that, the dielectric film 20 extends in a direction parallel to the surfaces of the electrodes 21a and 21b, as indicated by white arrows in FIG. As a result, the electrostrictive actuator 1 outputs a driving force in the horizontal direction in the figure.

  Here, the thickness of the dielectric film (the acrylic rubber of the present invention) may be appropriately determined according to the application of the electrostrictive actuator. For example, the thickness of the dielectric film is desirably thinner from the viewpoints of downsizing the electrostrictive actuator, driving at a low potential, and increasing the amount of displacement. In this case, it is desirable that the thickness of the dielectric film be 1 μm or more and 1000 μm (1 mm) or less in consideration of dielectric breakdown properties and the like. A more preferable range is 5 μm or more and 200 μm or less.

  Moreover, the material of the electrode is not particularly limited. For example, an electrode obtained by applying a paste or paint in which oil or elastomer is mixed as a binder to a conductive material made of a carbon material such as carbon black or carbon nanotube can be used. It is desirable that the electrode can expand and contract according to the expansion and contraction of the dielectric film. When the electrode expands and contracts together with the dielectric film, the deformation of the dielectric film is not easily disturbed by the electrode, and a desired displacement amount can be obtained more easily.

  Further, when a laminated structure in which a plurality of dielectric films and electrodes are alternately laminated, a larger force can be generated. As a result, the output of the electrostrictive actuator is increased, and the counterpart member can be driven with a greater force.

  Next, the present invention will be described more specifically with reference to examples.

<Manufacture of acrylic rubber>
(1) Production of Acrylic Rubber of Examples An acrylic rubber composition was prepared by blending the predetermined raw materials shown in Table 1 below, and crosslinked by irradiation with ultraviolet rays (UV) to produce acrylic rubber of the examples. First, in Table 1, an epoxy group-containing acrylic ester polymer was dissolved in MEK. Subsequently, an ionic photoacid generator (crosslinking agent) and a plasticizer were added to the MEK solution, and the mixture was stirred and mixed to prepare a solution-like acrylic rubber composition. Next, the prepared acrylic rubber composition was applied onto a PET substrate by a bar coating method. After the coating film was dried, the whole substrate was put in a UV irradiation apparatus, and the coating film was irradiated with UV for about 30 seconds. Then, the coating film was peeled off from the base material to obtain a thin-film acrylic rubber. The obtained acrylic rubber was used as the acrylic rubber film of the example. The thickness of the acrylic rubber film was about 50 μm.

(2) Production of Acrylic Rubber of Comparative Example An acrylic rubber composition was prepared by blending predetermined raw materials shown in Table 1 below, and press-crosslinked under heating to produce two types of acrylic rubber of the comparative example. First, in Table 1, an epoxy group-containing acrylic ester polymer and a processing aid were kneaded with a roll kneader. Subsequently, an acrylic rubber composition was prepared by adding a vulcanization accelerator and mixing and dispersing in a roll kneader. Next, the prepared acrylic rubber composition was formed into a thin sheet. It was filled in a mold and press-crosslinked at 170 ° C. for about 30 minutes to obtain a thin-film acrylic rubber. The obtained acrylic rubber was used as the acrylic rubber film of Comparative Examples 1 and 2. The thickness of each acrylic rubber film was about 200 μm.

Table 1 shows the types and amounts of raw materials used, crosslinking conditions, and the like. Table 1 also shows the measurement results of tensile properties and relative permittivity, which will be described later. In Table 1, “Vinizer”, “Lunac”, “Varnock”, and “Noxeller” are registered trademarks.

<Physical property evaluation of acrylic rubber>
(1) Tensile property Tensile property was measured about each acrylic rubber film of the manufactured Example and the comparative example. The tensile properties were measured according to JIS K6251 (test piece: No. 5 type dumbbell). The results are summarized in Table 1 above.

  As shown in Table 1, there was almost no difference in tensile properties between the example and the comparative example. That is, it was confirmed that the acrylic rubber of the present invention using an ionic photoacid generator as a crosslinking agent has a tensile property equivalent to that of a conventional product.

(2) Dielectric constant Moreover, the dielectric constant was measured about each manufactured acrylic rubber film of the Example and the comparative example. For the measurement of relative permittivity, each acrylic rubber film is placed in a sample holder (Solartron Co., 12962A type), and a dielectric constant measurement interface (manufactured by the company, 1296 type) and a frequency response analyzer (manufactured by the company, 1255B type) are installed. Measured in combination. The results are summarized in Table 1 above.

  As shown in Table 1, the relative dielectric constants of the acrylic rubber films of Comparative Examples 1 and 2 are as low as less than 10, whereas the relative dielectric constant of the acrylic rubber film of the example is 40 or more. It became high. Thus, it was confirmed that the acrylic rubber of the present invention containing an ionic photoacid generator has a high dielectric constant.

  In the production of the acrylic rubber of the example, the crosslinking reaction was completed in about 30 seconds. Thus, by using an ionic photoacid generator as a crosslinking agent, the crosslinking time required for about 30 minutes in the production of the acrylic rubber of the comparative example could be significantly shortened.

<Response evaluation of electrostrictive actuator>
Next, electrostrictive actuators were constructed using the acrylic rubber films of the examples and comparative examples, and the responsiveness of the actuators was evaluated. First, an experimental apparatus and an experimental method will be described.

  Dielectric films were prepared from the acrylic rubber films of the examples and comparative examples. Electrostrictive actuators (simply referred to as “actuators” in this embodiment) were configured by attaching electrodes made of conductive paste mixed with conductive carbon and oil to the upper and lower surfaces of the produced dielectric film. . Hereinafter, the manufactured actuator is referred to as an actuator of an example or a comparative example corresponding to the type of dielectric film. FIG. 3 shows a top view of the manufactured actuator. FIG. 4 shows a sectional view taken along line IV-IV in FIG.

As shown in FIGS. 3 and 4, the actuator 3 includes a dielectric film 30 and a pair of electrodes 31 a and 31 b. The dielectric film 30 has a circular thin film shape with a diameter of 70 mm. The dielectric film 30 is disposed in a state of being stretched in the biaxial direction at a stretch rate of 100%. Here, the stretching ratio is a value calculated by the following equation (1).
Stretch rate (%) = {√ (S ₂ / S ₁ ) −1} × 100 (1)
[S ₁ : Dielectric film area before stretching (natural state), S ₂ : Dielectric film area after biaxial stretching]

  The pair of electrodes 31a and 31b are arranged so as to face each other in the vertical direction with the dielectric film 30 interposed therebetween. The electrodes 31 a and 31 b have a circular thin film shape with a diameter of about 27 mm, and are arranged substantially concentrically with the dielectric film 30. A terminal portion 310a protruding in the diameter increasing direction is formed on the outer peripheral edge of the electrode 31a. The terminal portion 310a has a rectangular plate shape. Similarly, a terminal portion 310b projecting in the diameter increasing direction is formed on the outer peripheral edge of the electrode 31b. The terminal portion 310b has a rectangular plate shape. The terminal portion 310b is disposed at a position facing the terminal portion 310a by 180 °. Each of the terminal portions 310a and 310b is connected to the power source 4 through a conducting wire.

  When a voltage is applied between the electrodes 31a and 31b, an electrostatic attractive force is generated between the electrodes 31a and 31b, and the dielectric film 30 is compressed. As a result, the thickness of the dielectric film 30 is reduced and extends in the diameter expansion direction. At this time, the electrodes 31a and 31b are also integrated with the dielectric film 30 and extend in the diameter increasing direction. A marker 50 is previously attached to the electrode 31a. The displacement of the marker 50 was measured by the displacement meter 5 and used as the displacement amount of the actuator 3.

Next, experimental results will be described. In FIG. 5, the displacement rate with respect to the applied voltage of each actuator of an Example and a comparative example is shown. Here, the displacement rate on the vertical axis is a value calculated by the following equation (2).
Displacement rate (%) = (displacement amount / radius of electrode) × 100 (2)

  As shown in the graph of FIG. 5, according to the actuator of the example, a larger displacement rate was obtained when the same voltage was applied as compared with the actuators of Comparative Examples 1 and 2. That is, according to the actuator of the example, it is understood that the applied voltage can be further lowered when a desired displacement rate is obtained.

  From the above results, it was confirmed that the acrylic rubber of the present invention has tensile properties equivalent to those of conventional products and has a high dielectric constant. In addition, it was confirmed that a large displacement can be obtained at a low voltage according to the electrostrictive actuator using the acrylic rubber of the present invention. Moreover, according to the manufacturing method of this invention, since crosslinking time can be shortened, it was confirmed that the acrylic rubber of this invention can be manufactured simply and in a short time.

  The acrylic rubber of the present invention is used for electrostrictive actuators used in, for example, artificial muscles for industrial, medical, and welfare robots, small pumps for cooling electronic components, medical devices, and the like. The electrostrictive actuator using the acrylic rubber of the present invention can be used as a substitute for all actuators such as a mechanical actuator such as a motor and a piezoelectric element actuator.

It is a figure which shows the generation mechanism of the acid in a sulfonium salt type | system | group ionic photo-acid generator. It is a cross-sectional schematic diagram of an electrostrictive actuator using the acrylic rubber of the present invention. It is a top view of the electrostrictive actuator used for response evaluation. It is IV-IV sectional drawing in FIG. It is a graph which shows the displacement rate with respect to the applied voltage of each electrostrictive actuator.

Explanation of symbols

1: Electrostrictive actuator 20: Dielectric film 21a, 21b: Electrode 22: Power supply 3: Actuator 30: Dielectric film 31a, 31b: Electrode 310a, 310b: Terminal section 4: Power supply 5: Displacement meter 50: Marker

Claims (5)

  An acrylic rubber for electrostrictive actuators obtained by crosslinking an acrylic rubber composition containing an epoxy group-containing acrylic ester polymer and an ionic photoacid generator.   The acrylic rubber for an electrostrictive actuator according to claim 1, wherein the ionic photoacid generator is at least one selected from a sulfonium salt and an iodonium salt.   The acrylic rubber for electrostrictive actuators according to claim 1 or 2, wherein the relative dielectric constant is 10 or more. An acrylic rubber composition preparation step for preparing an acrylic rubber composition containing an epoxy group-containing acrylic ester polymer and an ionic photoacid generator;
A crosslinking step of irradiating the acrylic rubber composition with light and crosslinking;
A method for producing acrylic rubber for electrostrictive actuators.   The electrostrictive actuator according to claim 4, wherein the compounding amount of the ionic photoacid generator is 0.1 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the epoxy group-containing acrylic ester polymer. Method for manufacturing acrylic rubber.

Images