JP2007063337A - Highly dielectric elastomer composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly dielectric elastomer composition compounded with a highly dielectric ceramic which has a broader particle diameter distribution, can densely be filled, and has an excellent dielectric characteristic, and to provide a method for producing the highly dielectric elastomer composition. <P>SOLUTION: This highly dielectric elastomer composition comprising an elastomer and a highly dielectric ceramic is obtained by subjecting a reaction raw material containing at least metal powder as a heat-generating source and a substance as an oxygen-supplying source to a combustion synthesis method at an adiabatic flame temperature of ≥1,500°C and then calcining the synthesized product. The elastomer is preferably ethylene-propylene rubber, and the metal powder is preferably a group 4 element having a specific surface area of 0.01 to 2 m<SP>2</SP>/g. The substance as the oxygen-supplying source is preferably sodium perchlorate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a high dielectric elastomer composition and a method for producing the high dielectric elastomer composition.

In recent years, with the remarkable spread of patch antennas used for mobile phones, cordless phones, RFID, etc., lens antennas such as radio telescopes and millimeter wave radars, and the remarkable development of satellite communication devices, the frequency of communication signals has increased and the frequency of communication devices has increased. Further downsizing is desired.
As for the frequency of the communication signal and the size of the communication device, for example, when the relative dielectric constant of the antenna substrate incorporated in the communication device is increased, the frequency and size can be further reduced. The relative dielectric constant is a parameter indicating the degree of polarization inside the dielectric, and the higher the relative dielectric constant of the high dielectric elastomer composition used for the antenna material, the shorter the wavelength of the signal propagating through the electronic component circuit, The signal becomes high frequency. Therefore, if an electronic component having a high relative dielectric constant can be used, the frequency can be increased, the circuit can be shortened, and the communication device can be downsized.

In order to produce a high dielectric elastomer composition, a high dielectric ceramic powder is generally blended with the elastomer.
However, for the synthesis of conventional high dielectric ceramics, external heating must be performed using a furnace capable of heating from about 1000 ° C. to about 2000 ° C. For this reason, the synthesis of ceramics requires enormous energy and a large heating mechanism, which increases the manufacturing cost. As a manufacturing method in which external heating is not performed, synthesis of ceramic powder by a combustion synthesis method has been proposed (see Patent Document 1). The combustion synthesis method is a method of synthesizing substances in a chain manner by utilizing a large amount of chemical heat reaction released at the time of compounding without requiring external heating.
In the production method according to Patent Document 1, three kinds of raw materials, one kind of metal oxide and two kinds of different metal elements, are used as starting materials, and two kinds of intermetallic compounds or non-oxide ceramics and oxide ceramics are synthesized. ing. For example, after mixing nickel oxide powder, aluminum powder, and alumina powder to form a compact, it is stored in a high-pressure reaction vessel, and the upper end surface of the compact is ignited in an argon atmosphere to oxidize and burn the aluminum powder. The combustion reaction proceeds in a chained manner while the reduced nickel reacts with the excessively added aluminum to synthesize NiAl. As a result, an ingot of NiTi that is one of intermetallic compounds can be manufactured without external heating.

However, in the above case, Al ₂ O ₃ synthesized simultaneously is said to be easily obtained from NiTi due to the difference in wettability, specific gravity, viscosity, melting point and thermodynamic stability with respect to NiTi. It is difficult to accurately separate these two kinds of composites, and there is a problem that the ceramic obtained by this manufacturing method is not a high dielectric material.
In addition, commercially available dielectric ceramic powders have a uniform average particle size and have a problem that it is difficult to highly fill the elastomer in order to increase the dielectric constant.
Japanese Patent Laid-Open No. 5-9009

  The present invention has been made in order to cope with such problems, and is obtained by combustion synthesis. The present invention is capable of widening the particle size distribution, and has high dielectric properties with excellent dielectric properties that can be highly filled. It is an object of the present invention to provide a high dielectric elastomer composition containing ceramics and a method for producing the high dielectric elastomer composition.

The high dielectric elastomer composition of the present invention is a high dielectric elastomer composition obtained by blending high dielectric ceramics with an elastomer, and the high dielectric ceramics comprises a metal powder as a heat source and an oxygen supply source. It is characterized in that it is obtained by synthesizing a reaction raw material containing at least a substance to become a combustion synthesis method having an adiabatic flame temperature of 1500 ° C. or higher and then calcining.
The elastomer is an ethylene propylene rubber.
The metal powder is a group 4 element having a specific surface area of 0.01 to ² m ² / g.
The substance serving as the oxygen supply source is sodium perchlorate.

  The method for producing a highly dielectric elastomer composition of the present invention comprises a mixing step of mixing a reaction material containing at least a metal powder serving as a heat source and a substance serving as an oxygen supply source in a predetermined ratio, and mixing in the predetermined ratio A method for producing a high dielectric elastomer composition comprising: a reaction step of reacting the resulting mixture by a combustion synthesis method; and a blending step of blending the high dielectric ceramic after combustion synthesis with the elastomer, the reaction step It has the calcination process which calcinates the reaction product obtained by this.

The high dielectric elastomer composition of the present invention can be easily obtained by calcining a high dielectric ceramic obtained by a combustion synthesis method and then blending it into the elastomer.
By performing the calcination treatment, impurities such as NaCl remaining in the high dielectric ceramic can be removed, the crystal structure is stabilized, and a dielectric powder having the same structure as the sintered body can be obtained. A high dielectric elastomer composition exhibiting a high dielectric constant and a low dielectric loss tangent can be obtained by blending the calcined high dielectric ceramic with the elastomer.

The high dielectric elastomer composition of the present invention is a reaction product obtained as a high dielectric ceramic by synthesizing a reaction raw material containing at least a metal powder serving as a heat source and a substance serving as an oxygen supply source by a combustion synthesis method. After calcining the product, a high dielectric elastomer composition can be obtained by blending with the elastomer.
As a method for producing the high dielectric ceramic, for example, a reaction raw material containing at least a titanium metal powder serving as a heat source and a substance serving as an oxygen supply source is added to (i) a composition formula MTiO ₃ (M is a group 2 element) (B) BaRe ₂ Ti _m O _{2m + 4} (where 3 ≤ m ≤ 7; m is an integer; Re Is a method in which Re ₂ O ₃ and BaO ₂ are added and synthesized by combustion for the purpose of obtaining an oxide-based dielectric ceramic represented by a rare earth element).

The metal powder serving as a heat source that can be used in the present invention is preferably a Group 4 element. More preferably, it is a Group 4 A element. Specific examples include titanium (Ti), zirconium (Zr), and hafnium (Hf). Among these, Ti is preferable because ceramics having excellent dielectric properties can be obtained.
Group 4 A elements can be used alone or in combination. In addition, as elements that can be blended simultaneously with these Group 4 A elements, rutherfordium (Rf), tin (Sn), antimony (Sb), tellurium (Te), lanthanum (La), cerium (Ce), prasedium (Pr), Examples thereof include neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), bismuth (Bi), polonium (Po), and astatine (At).

The shape of the metal containing a Group 4 element that can be used in the present invention is preferably a fine powder, and has a specific surface area of 0.01 to ² m ² / g. A preferable specific surface area is 0.03 to 0.6 m ² / g because the combustion wave propagates and is easy to handle. When the specific surface area is less than 0.01 m ² / g, the contact area between the metal powder that is the heat source and the peroxide that is the oxygen supply source is small, so the combustion wave does not propagate and high dielectric ceramics cannot be synthesized. There is. In addition, metal powders having a specific surface area exceeding 2 m ² / g are not preferable because they are extremely active and difficult to handle. In the present invention, the specific surface area of the metal powder is a value measured by the BET method.

Even when the average particle diameter of the metal fine powder that can be used for combustion synthesis is the same, a difference in reactivity was recognized when the specific surface area was different. That is, when a metal powder having a specific surface area larger than that of a spherical shape was used, the combustion synthesis reaction proceeded more rapidly. Examples of the shape having a large specific surface area include particles having a plurality of irregularities formed on the surface of spherical particles, particles having an irregular shape as a whole, or a combination thereof.
The average particle size that can be used in the present invention is 150 μm or less, preferably 0.1 to 100 μm. If it exceeds 150 μm, mixing with other raw materials becomes insufficient, and combustion waves may not propagate.
An image analysis method is preferable as a method for measuring the average particle diameter of particles having irregularities formed on the surface or an irregular shape.

The element containing a Group 2 element is preferably a Group 2 element alone, more preferably a Group 2 A element. Specific examples include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). Among these, Ca, Sr, and Ba are the above metal powders. Is preferable because ceramics having excellent dielectric properties can be obtained.
Group 2 A elements can be used alone or in combination. Examples of elements that can be blended simultaneously with these Group 2 A elements include Rf, Sn, Sb, Te, La, Ce, Pr, Nd, Pm, Sm, Eu, Bi, Po, and At.

Group 2 A elements are used in the form of carbonates. Examples of carbonates composed of Group 2 A elements include BeCO ₃ , MgCO ₃ , CaCO ₃ , SrCO ₃ , BaCO ₃ , and RaCO ₃ . Of these, CaCO ₃ , SrCO ₃ , and BaCO ₃ are particularly preferable because ceramics having excellent dielectric properties can be obtained.

In the present invention, the oxygen source includes chlorates such as KClO ₃ , NaClO ₃ and NH ₄ ClO ₃ , perchlorates such as KClO ₄ , NaClO ₄ and NH ₄ ClO ₄ , and chlorite such as NaClO _2. Salts, bromates such as KBrO ₃ , nitrates such as KNO ₃ , NaNO ₃ and NH ₄ NO ₃ , iodates such as NaIO ₃ and KIO ₃ , permanganic acid such as KMnO ₄ and NaMnO ₄ .3H ₂ O Salts, dichromates such as K ₂ Cr ₂ O ₇ , (NH ₄ ) ₂ Cr ₂ O ₇ , periodates such as NaIO ₄ , metaiodic acids such as HIO ₄ · 2H ₂ O, CrO ₃ Anhydrochromate such as NaNO ₂ , calcium hypochlorite trihydrate such as Ca (ClO) ₂ .3H ₂ O, and the like.
Among these, perchlorates are preferable, and NaClO ₄ is particularly preferable because it is easy to remove NaCl as a by-product.

As an example of the high dielectric ceramics that can be used in the present invention, a case where barium titanate, which is an example of a ceramic represented by the composition formula MTiO ₃ (M is a group 2 element), is synthesized by combustion will be described below.
Barium titanate, which is a high dielectric ceramic, is produced according to the following chemical reaction formula. The group 4 metal powder and group 2 carbonate which are each reaction raw material mix | blend the quantity corresponded to each molar mass required for reaction, but the oxygen generating substance can mix | blend the molar mass more than required for reaction.

Ti + BaCO ₃ +0.5 NaClO ₄ → BaTiO ₃ + CO ₂ ↑ + 0.5 NaCl

The mixing of the reaction raw materials containing at least a Group 4 metal powder, a Group 2 carbonate, and an oxygen generating substance can be used without particular limitation such as mixing using a ball mill or a mortar. The mixture used is preferred.
The mixed powder is put into a crucible and combusted and synthesized. The material of the crucible is preferably non-oxide carbon (C), silicon carbide (SiC), silicon nitride Si ₃ N ₄ or the like. Among these, a carbon (C) material is preferable because it is excellent in heat conduction and shape workability.
As a method for charging the mixed powder into the crucible, there can be used a method in which the mixed powder is laid down in a powder bed, compressed after being laid down, or pressed into a crucible into a crucible.

Regarding the conditions of the combustion synthesis method, the adiabatic flame temperature of the reaction system is 1500 ° C or higher. This is because the combustion wave propagates at 1500 ° C. or higher.
Combustion synthesis is performed in a chamber, and the atmosphere is preferably a rare gas atmosphere such as helium (He), neon (Ne), argon (Ar), or krypton (Kr). Note that a nitrogen gas, carbon dioxide atmosphere, or the like can be used as long as the dielectric properties of the reaction product are not deteriorated. Also, oxygen gas can be used if the oxygen partial pressure can be controlled.
The method for igniting the mixed powder for initiating combustion synthesis is not particularly limited as long as the metal powder can ignite and generate heat. A method in which a carbon film is ignited to generate heat and used as a heat source and brought into contact with the mixed powder to ignite and generate heat is preferable because it is excellent in handling.

In the combustion synthesis reaction, a chemical reaction proceeds simultaneously and frequently from the ignition portion without requiring external heating, and various non-stoichiometric compounds are synthesized. For this reason, in the present invention, the blending ratio of the Group 4 metal powder, the Group 2 carbonate, and the oxygen generating substance is important.
By performing the combustion synthesis reaction at the above-mentioned blending ratio, a high dielectric ceramic having a relative dielectric constant of 15 or more and a dielectric loss tangent of less than 0.01 can be obtained. This high-dielectric ceramic can be refined with a mortar and pestle, ball mill, jet mill, or other pulverizer to obtain a high-dielectric ceramic that can be adjusted to an average particle size of 3 μm and a standard deviation (3σ value) within 3.5 μm. . When the standard deviation (3σ) is within this range, the particle size distribution becomes wide and high packing is possible.
The average particle size of the high dielectric ceramic powder obtained by the combustion synthesis method and usable in the present invention is 0.01 μm to 100 μm, preferably 0.1 μm to 20 μm, and more preferably 0.1 μm to 3 μm. If the average particle size is less than 0.01 μm, the particle weight is light, so that it may be scattered during measurement, or it may be bulky and the volume of the mixer may be increased. On the other hand, if it exceeds 100 μm, it is not preferable because it may cause variations in dielectric properties within the elastomer.

  The reaction product is agglomerated in the crucible. The pulverization of the reaction product carried out for the purpose of removing unreacted products and by-products remaining in the reaction product or for post-processing is not particularly limited as long as the average particle size is 100 μm or less. It can be carried out using a jet mill, ball mill, mortar and pestle. When the average particle diameter exceeds 100 μm, the cleaning effect in the case of cleaning becomes insufficient, and the ion-binding salt as a by-product tends to remain.

The fine powder after the pulverization step may contain an ion-binding salt that is a by-product. For example, when NaClO ₄ is used as a raw material, NaCl is generated, and when KClO ₄ is used as a raw material, KCl is generated. These salts can be removed by washing with water.
When salts are present in the synthetic powder after the combustion synthesis reaction, the sinterability is hindered. As a standard for reducing the salt to such an extent that the sinterability is not hindered, the electrical conductivity of the cleaning liquid is 150 μS / cm or less. That is, regardless of the number of washings and the amount of washing, the electric conductivity of the washing water after washing should be 150 μS / cm or less when the synthetic powder is washed with water.

The electrical conductivity of the water used for cleaning is preferably less than 50 μS / cm. When it is 50 μS / cm 2 or more, the electrical conductivity of the cleaning liquid increases even if the amount of eluted ionic substances such as Na ⁺ and Cl ⁻ is sufficiently small. As the washing water having an electric conductivity of less than 50 μS / cm, pure water such as distilled water is particularly preferred for handling. The refined synthetic powder and cleaning liquid are put into a cleaning container, and ultrasonic cleaning is performed, and by-products are converted into ions such as Na ⁺ and Cl ⁻ and eluted in pure water. The removal amount can be increased by increasing the number of times the cleaning liquid is replaced or increasing the amount of the cleaning liquid with respect to the synthetic powder. In order to promote elution, it is also effective to raise the temperature of the cleaning solution. When the residual amount of the ionic substance as a by-product increases, it is not preferable because the ionic substance inhibits sintering when the ceramic powder is fired. As a technique for managing residual ionic substances, there is a measurement of electrical conductivity of a cleaning liquid. If the electric conductivity of the washing water after washing exceeds 150 μS / cm, it is not preferable because the sinterability of the high dielectric ceramic is inhibited.

The highly dielectric elastomer composition of the present invention can be easily obtained by rinsing and calcining the highly dielectric ceramic obtained by the combustion synthesis method and then blending it into the elastomer. .
Although the calcining treatment conditions depend on the contents of unreacted substances and impurities remaining in the high dielectric ceramic, the calcining temperature is preferably 850 to 1200 ° C., which is 1500 ° C. or less of the adiabatic flame temperature, The time is preferably 0.5-3 hours. In order to maintain high dielectric properties and reduce the content of unreacted substances and impurities, it is preferable to calcine for a long time in a low temperature region of calcining conditions.
By calcining the high dielectric ceramic obtained by the combustion synthesis method, impurities such as unreacted substances and NaCl remaining in the high dielectric ceramic can be removed, and the crystal structure of the high dielectric ceramic is stabilized. A dielectric powder having the same structure as the sintered body can be obtained. A high dielectric elastomer composition exhibiting a high dielectric constant and a low dielectric loss tangent can be obtained by blending the calcined high dielectric ceramic with the elastomer.

A high dielectric elastomer composition having a relative dielectric constant of 15 or more is obtained by blending a high dielectric ceramic powder produced by a combustion synthesis method and an elastomer.
Natural rubber elastomers and synthetic rubber elastomers can be used in the high dielectric elastomer composition of the present invention.
Natural rubber-based elastomers include natural rubber, chlorinated rubber, hydrochloric acid rubber, cyclized rubber, maleated rubber, hydrogenated rubber, and vinyl monomers such as methyl methacrylate, acrylonitrile, and methacrylic acid ester grafted onto the double bond of natural rubber. Examples thereof include a graft-modified rubber, a block polymer obtained by roughening natural rubber in the presence of a monomer in a nitrogen stream. These include natural rubber as a raw material and elastomers from synthetic cis-1,4-polyisoprene as a raw material.

  Synthetic rubber elastomers include isobutylene rubber, ethylene propylene rubber, ethylene propylene diene rubber, ethylene propylene terpolymer, polyolefin elastomer such as chlorosulfonated polyethylene rubber, styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene- Styrene elastomers such as styrene copolymer (SBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), isoprene rubber, urethane rubber, epichlorohydrin rubber, silicone rubber, nylon 12, butyl rubber, butadiene rubber, polynorbornene rubber, acrylonitrile- Examples thereof include butadiene rubber.

  The said elastomer can be used 1 type or in mixture of 2 or more types. Further, one or two thermoplastic resins can be blended and used within a range that does not impair the elasticity of the elastomer. When one or more kinds selected from natural rubber elastomers and / or synthetic nonpolar elastomers are used as the elastomer that can be used in the present invention, a highly dielectric elastomer excellent in electrical insulation can be obtained. Therefore, it can be preferably used for applications requiring insulation properties. Examples of the synthetic non-polar elastomer include ethylene propylene rubber, isobutylene rubber, isoprene rubber, and silicone rubber. In particular, since ethylene propylene rubber has a very low dielectric loss tangent, it can be preferably used for electronic parts such as antennas and sensors.

  The blending ratio of the high dielectric ceramic is such an amount that the dielectric constant of the high dielectric elastomer composition can be maintained at 15 or more and the moldability that can be obtained for an electronic component such as an antenna can be maintained. For example, 300 to 2000 parts by weight (phr) of high dielectric ceramic can be blended with 100 parts by weight (phr) of elastomer.

  In the present invention, in order not to impede the effects of the present invention, (1) In order to improve the affinity and bondability of the interface between the elastomer and the ceramic powder and improve the mechanical strength, a silane coupling agent, titanate Coupling agents such as coupling agents and zirconia aluminate coupling agents, (2) In order to improve plating properties for electrode formation, particulate fillers such as talc and calcium pyrophosphate, and (3) heat Antioxidants to further improve stability, (4) Light stabilizers such as ultraviolet absorbers to improve light resistance, and (5) Halogen or phosphorous to further improve flame retardancy. (6) Impact resistance imparting agent to improve impact resistance, (7) Lubricant, rocking property improver (solid lubricant, liquid lubrication to improve lubricity Agent), (8) coloring For this purpose, colorants such as dyes and pigments, (9) plasticizers for adjusting physical properties, crosslinking agents such as sulfur and peroxides, and (10) vulcanization accelerators for proceeding with vulcanization are blended. be able to.

  Further, the high dielectric elastomer composition of the present invention includes glass fiber, alkali metal titanate fiber such as potassium titanate whisker, titanium oxide fiber, magnesium borate whisker and boric acid within the range not impairing the object of the present invention. Various organic or inorganic fillers such as boric acid metal salt fibers such as aluminum whiskers, silicate metal fibers such as zinc silicate whiskers and magnesium silicate whiskers, carbon fibers, alumina fibers, and aramid fibers can be used in combination.

  The method for producing the highly dielectric elastomer composition of the present invention is not particularly limited, and various mixed molding methods can be used. For example, a method of producing by kneading with a twin screw extruder is preferably used. Immediately, a molded product may be obtained by injection molding, extrusion molding, or the like, or a molding material such as pellets, rods, or plates.

  The high dielectric elastomer composition of the present invention is excellent in dielectric properties because it contains a high dielectric ceramic produced by a combustion synthesis method. Therefore, a high-frequency electronic component that operates at 100 MHz using this elastomer composition can further increase the signal propagation speed in the high-frequency band, and can be downsized due to the wavelength shortening effect. Therefore, it is suitable for a patch antenna used for a mobile phone, a cordless phone, an RFID, etc., a lens antenna such as a radio telescope, a millimeter wave radar, and the like.

Reference Synthesis Example 1 to Reference Synthesis Example 6
High dielectric ceramics were synthesized by the following method.
A mixed powder was obtained by mixing Group 4 metal powders, Group 2 carbonates, and oxygen-generating substances having different specific surface areas shown in Table 1 for 5 hours at a molar ratio shown in Table 1 using a ball mill. A carbon crucible was installed in the chamber in the synthesizer, and the mixed powder (100 g) was spread in the carbon crucible, and a carbon film for ignition was brought into contact with a part of the mixed powder to close the chamber. After reducing the residual oxygen in the chamber using a vacuum pump, argon (Ar) gas was sealed, and the internal pressure of the chamber was set to 0.1 MPa.

Combustion waves propagated for all compositions of Reference Synthesis Examples 1 to 6, and synthetic powder and by-product (NaCl) were obtained by the combustion synthesis method. The synthetic powder was pulverized using an alumina mortar to obtain an unwashed high dielectric ceramic powder having an average particle size (μm) and particle size distribution (3σ value, μm) shown in Table 2.
The obtained unwashed high dielectric ceramic powder was sufficiently washed with water, and NaCl adhered to the powder was removed to obtain an uncalcined high dielectric ceramic.
The obtained uncalcined high dielectric ceramic powder was calcined at the temperature and time shown in Table 1, and impurities remaining in the powder were removed to obtain a high dielectric ceramic.
The crystal phase of the obtained high dielectric ceramic powder was identified using an X-ray diffractometer (XRD). The results are shown in Table 2 as the ceramic composition.
The relative dielectric constant and dielectric loss tangent were measured by the following methods.
1% by weight of a molding binder (polyvinyl butyral resin) was added to and mixed with the obtained high dielectric ceramic powder. Next, the mixed powder was put into a 10 mm × 80 mm mold and a pressure of 1.5 ton / cm ² was applied to obtain a green body (10 mm × 90 mm × 3 mm). This green body was held at 600 ° C. for 1 hour to remove organic components, and then fired at 1300 ° C. for 3 hours. The obtained sintered body was processed into a 70 mm × 1.5 mm × 1.5 mm test piece, and the dielectric constant and dielectric loss tangent were measured in the 1 GHz and 5 GHz frequency bands using the cavity resonator method. Here, relative permittivity and dielectric loss tangent are values at 25 ° C. The results are shown in Table 2.
Moreover, the content (ppm) of impurities SrCO ₃ , CaCO ₃ and Na ₂ O is identified by XRD, and the content of the layer due to the minute peak is determined from the ratio of the main component peak to the minute peak. Calculated as a rate. Moreover, it measured using the fluorescent X ray analysis method (oxide conversion) as needed. The results are shown in Table 2.

Reference Comparative Example 1 to Reference Comparative Example 3
Using the non-calcined high dielectric ceramic powder obtained in Reference Synthesis Example 1, Reference Synthesis Example 5 and Reference Synthesis Example 6, impurities were removed without performing calcination, and Reference Comparative Example 1 and Reference Comparative Example were respectively used. 2 and Reference Comparative Example 3 were obtained. Table 2 shows the composition, relative dielectric constant, dielectric loss tangent, average particle size (μm), particle size distribution (3σ value, μm) and impurity content (ppm) of the obtained high dielectric ceramics.

Examples 1 to 6
Ceramic powder (reference synthesis examples 1 to 6) synthesized by combustion synthesis and then calcined with 100 parts by weight of ethylene propylene rubber (Mitsui Chemicals Co., Ltd .: EPT-3095) and carbon black (manufactured by Tokai Carbon Co., Ltd .: Seast S), vulcanization accelerator and processing aid, etc. are blended in the blending ratios shown in Table 3, kneaded with a pressure kneader, and then formed into 80 mm x 80 mm x 1.5 mm by heat compression molding. Got the body. The vulcanization conditions are 170 ° C x 20 minutes each.
The process oil is PW-380 manufactured by Idemitsu Kosan Co., Ltd., the zinc oxide is META-Z L-40 manufactured by Inoue Coal Industry, the stearic acid is Lunac S-30 manufactured by Kao Corporation, and the anti-aging agent is Seiko. Non-flex RD-G manufactured by Kagaku Co., Soccinol M manufactured by Sumitomo Chemical Co., Ltd. was used as the vulcanization accelerator, and Kayak Mill D40 manufactured by Kayaku Akzo Co., Ltd. was used as the peroxide crosslinking agent. A 1.5 mm x 1.5 mm x 80 mm strip test piece was machined from the resulting compact, and dielectric properties (dielectric constant and dielectric loss tangent) were measured in the 1 GHz band and 5 GHz band by the cavity resonator method. did. Table 3 shows the measurement results. In all the examples, the relative dielectric constant is 10 or more and the dielectric loss tangent is 0.007 or less.

Comparative Examples 1 to 6
Table 3 shows the blending ratio of uncalcined high dielectric ceramic powder (Reference Comparative Examples 1 to 3) and other compounding agents with respect to 100 parts by weight of ethylene propylene rubber (Mitsui Chemicals Co., Ltd .: EPT-3095). After mixing with a pressure kneader, a compact of 80 mm × 80 mm × 1.5 mm was obtained by heat compression molding. The vulcanization conditions are 170 ° C x 20 minutes each.
A 1.5 mm x 1.5 mm x 80 mm strip test piece was machined from the resulting compact, and dielectric properties (dielectric constant and dielectric loss tangent) were measured in the 1 GHz band and 5 GHz band by the cavity resonator method. did. Table 3 shows the measurement results.

Comparative Example 7 and Comparative Example 8
Dielectric ceramic powder (manufactured by Kyoritsu Materials Co., Ltd .: ST-NAS) is 100 parts by weight of ethylene propylene rubber (Mitsui Chemicals Co., Ltd .: EPT-3095), 600 parts by weight in Comparative Example 7 and 900 parts by weight in Comparative Example 8 The other compounding agents were blended in the blending ratios shown in Table 3, respectively, kneaded with a pressure kneader, and then a compact of 80 mm × 80 mm × 1.5 mm was obtained by heat compression molding. The vulcanization conditions are 170 ° C x 20 minutes each.
A 1.5 mm x 1.5 mm x 80 mm strip test piece was machined from the resulting compact, and dielectric properties (dielectric constant and dielectric loss tangent) were measured in the 1 GHz band and 5 GHz band by the cavity resonator method. did. Table 3 shows the measurement results.

Comparative Example 9 and Comparative Example 10
In Comparative Example 9, 1200 parts by weight of dielectric ceramic powder (manufactured by Kyoritsu Materials Co., Ltd .: ST-NAS) and 1500 parts by weight in Comparative Example 10 with respect to 100 parts by weight of ethylene propylene rubber (Mitsui Chemicals Co., Ltd .: EPT-3095) Other compounding agents were blended at the blending ratios shown in Table 3, respectively, and kneading was attempted with a pressure kneader. However, since the amount of dielectric ceramic powder blended was too large, it could not be homogeneously kneaded, and the dielectric properties were reduced. A molded product for measurement could not be obtained.

表３より各実施例では、未仮焼高誘電性セラミックス粉末を使用した高誘電性エラストマーの比較例１〜比較例６よりも優れた誘電正接を示し、市販の誘電性セラミックス粉末を使用した比較例７、比較例８と同等、または、優れた比誘電率、誘電正接を示した。

From Table 3, each example shows a dielectric loss tangent superior to Comparative Examples 1 to 6 of high dielectric elastomers using uncalcined high dielectric ceramic powders, and comparison using commercially available dielectric ceramic powders. The dielectric constant and dielectric loss tangent were the same as or superior to those of Example 7 and Comparative Example 8.

  The high dielectric elastomer composition of the present invention is obtained by calcining the high dielectric ceramic obtained by the combustion synthesis method and blending it into the elastomer, so that impurities such as NaCl remaining in the high dielectric ceramic can be removed. In addition, a dielectric powder having a stable crystal structure and the same structure as the sintered body can be obtained. For this reason, the high dielectric elastomer composition of the present invention has excellent dielectric properties, and can be suitably used for patch antennas used in mobile phones, cordless phones, RFIDs, etc., lens antennas such as radio telescopes and millimeter wave radars, and the like.

Claims (5)

A high dielectric elastomer composition obtained by blending a high dielectric ceramic with an elastomer,
The high dielectric ceramic is prepared by synthesizing a reaction raw material containing at least a metal powder as a heat source and a substance as an oxygen supply source by a combustion synthesis method with an adiabatic flame temperature of 1500 ° C. or higher, and calcining. A highly dielectric elastomer composition obtained.   The high dielectric elastomer composition according to claim 1, wherein the elastomer is ethylene propylene rubber. 3. The high dielectric elastomer composition according to claim 1, wherein the metal powder is a group 4 element having a specific surface area of 0.01 to ² m < ² > / g.   4. The high dielectric elastomer composition according to claim 1, wherein the oxygen source is sodium perchlorate. A mixing step in which a reaction raw material containing at least a metal powder serving as a heat generation source and a substance serving as an oxygen supply source are mixed in a predetermined ratio, and a reaction step in which the mixture mixed in the predetermined ratio is reacted by a combustion synthesis method; A method for producing a high dielectric elastomer composition comprising a blending step of blending a high dielectric ceramic after combustion synthesis with an elastomer,
A method for producing a highly dielectric elastomer composition comprising a calcining step of calcining the reaction product obtained in the reaction step.