JPH05135621A - Dielectric material - Google Patents

Abstract

PURPOSE:To realize a high, dielectric constant and a high dielectric loss and also arbitrarily adjust a dielectric constant and a dielectric loss by preparing a constitution where a surface active agent and a dispersion medium or a solid absorbent which supports the surface active agent and the dispersion medium are used. CONSTITUTION:A dielectric material is made up by using a surface active agent having a prescribed functional group and a dispersion medium which dispersedly holds the surface active agent or a solid absorbent which supports such a surface active agent and a dispersion medium which dispersedly holds them. In this case, at least one of quaternary ammonium base, hydroxyl group, sulfonic acid base, acid amide group, carboxylic acid base and phosphoric acid base is used as a functional group having the surface active agent. As the solid absorbent, geolite or active carbon is used. The surface active agent having such a prescribed functional group has good wave absorptivity (caused by a high dielectric loss), or has ionicity and molecular polarization and a high dielectric constant. It is therefore possible to arbitrarily adjust a dielectric characteristic by the chemical structure of the surface active agent and a filling quantity thereof.

Description

Detailed Description of the Invention

[0001]

The present invention has a high dielectric property (dielectric constant,
The present invention relates to a novel dielectric material that has a dielectric loss) and can be applied as a capacitor material or an electromagnetic wave absorbing material.

[0002]

2. Description of the Related Art As a conventional dielectric material, a material in which a ceramic powder having a high dielectric constant such as barium titanate is dispersed in resin or rubber is known.

[0003]

However, many of the conventional dielectric materials have a high dielectric constant but a low dielectric loss, and neither has a high dielectric constant or a high dielectric loss.
For example, a ceramic-based dielectric material has a dielectric constant of 10 and a dielectric loss angle of 0.001 at 2.45 GHz, and a rubber / resin-based dielectric material has a dielectric constant of 2 to 3 and a dielectric loss angle of 0 at 2.45 GHz. It was about 0.001.

The present invention has been made to solve the above problems, and an object thereof is to provide a novel dielectric material having a high dielectric constant and a high dielectric loss, and capable of arbitrarily adjusting the dielectric constant and the dielectric loss. Is.

[0005]

In order to achieve the above-mentioned object, the present invention provides a dielectric material of the present invention which comprises, as a functional group, at least a quaternary ammonium salt group, a hydroxyl group, a sulfonate group, an acid amide group and a carboxylate group. , A surfactant having any one of phosphate groups and a dispersion medium for dispersing and holding the same. Further, it is composed of a solid adsorbent carrying the above-mentioned surfactant and a dispersion medium for dispersing and holding the same. The solid adsorbent is preferably zeolite or activated carbon.

[0006]

It has been found that certain surfactants have excellent dielectric properties. The surfactant is composed of a hydrophobic part such as a long-chain alkyl group due to its molecular structure and a hydrophilic part such as a quaternary ammonium salt group, a hydroxyl group, a sulfonate group, an acid amide group, a carboxylate group, and a phosphate group. .. Among these, a surfactant having a functional group such as a quaternary ammonium salt group or a hydroxyl group has excellent radio wave absorption characteristics (due to high dielectric loss).

The excellent electromagnetic wave absorption property of water is caused by the deviation of charges in the molecule, that is, the dipole, but the surfactant having the above-mentioned structure also has the deviation of charges in the molecule. , Can be similarly explained.

Surfactants having a sulfonate group, an acid amide group, a carboxylate group, and a phosphate group (alkaline metals such as sodium are generally used as a salt-forming metal) are ionic and polarizable molecules. And has a high dielectric constant.

These can be used alone, but can also be dispersed and held in a dispersion medium such as resin or rubber to be used as a molded body.

Further, many of these surfactants are liquid at room temperature or have a low melting point, and when used at a high temperature, they melt to become a liquid. Therefore, as a result of studying a form that is easy to use by combining this carrier-solid adsorbent, it was found that zeolite and activated carbon are optimal. In particular, zeolite is an aluminosilicate having a three-dimensional fine structure and has a very strong chemical adsorption force.
Therefore, the surfactant supported on the zeolite is strongly adsorbed and fixed, and as a result, the surfactant is not separated and released even at a temperature higher than the melting point of the surfactant. Also,
When such a solid adsorbent is used, the dielectric properties of the fixed adsorbent itself are also taken into consideration. That is, although the zeolite alone has a weak radio wave absorption ability, it is presumed that this is due to the water adsorbed on the zeolite. Activated carbon itself has a radio wave absorption capability due to resistance loss.

[0011]

EXAMPLES Examples of the present invention will be described below.

Example 1 Quaternary ammonium salt type surfactants such as C ₁₇ H ₃₅ NH
_A predetermined amount was kneaded in non-density polyethylene using ₄ Cl as a dispersion medium to obtain a molded body. This product had a dielectric constant of 10 and a dielectric loss angle (tan δ) of 0.3 (frequency: 2.45 GH).
z).

Example 2 A molded product was obtained in the same manner as in Example 1 except that a nonionic (polyhydric alcohol) surfactant was used. This product had a dielectric constant of 10 and a dielectric loss angle (tan δ) of 0.2 (frequency: 2.45G).
Hz).

Example 3 A surfactant having a sulfonate group, an acid amide group, a carboxylate group, and a phosphate group (alkali metal such as sodium is generally used as a salt-forming metal) was prepared in the same manner as in Example 1. Each obtained a molded body. These materials have a dielectric constant of 30 and a dielectric loss angle (tan δ) of 0.00 as approximate values.
It was 05 (frequency 2.45 GHz).

The molded bodies of Examples 1 and 2 have sufficient characteristics as a radio wave absorber. Further, the molded body of Example 3 is sufficiently practical as a high dielectric constant material.

Example 4 The nonionic surfactant used in Example 2 was diluted with a solvent, and zeolite as a solid adsorbent was added to the diluted solvent and filtered.
The product obtained by drying was kneaded into, for example, low-density polyethylene as a dispersion medium to obtain a molded product. Dielectric properties of Example 2
Was similar to. Furthermore, this product did not liberate the surfactant even at a temperature above the melting point of the nonionic surfactant.

Example 5 The nonionic surfactant used in Example 2 was diluted with a solvent, activated carbon was added as a solid adsorbent therein, and the mixture was filtered and dried to obtain a dispersion medium having a low density, for example. The mixture was kneaded in polyethylene to obtain a molded body. This one has a dielectric constant of 3
The dielectric loss angle (tan δ) was 0.5 (frequency: 2.45 GHz).

As described above, in the above-mentioned structure, the dielectric material of the present invention can arbitrarily adjust the dielectric property from a low value to a high value depending on the chemical structure and the filling amount of the surfactant. Further, by supporting it on a solid adsorbent, a dielectric material that can withstand practical use even at a temperature equal to or higher than the melting point of the surfactant can be obtained.

Although low density polyethylene is used as the dispersion medium in the above embodiment, the present invention is not limited to this. Further, the surfactant is used by being supported on the solid adsorbent, but it may be coexistent without being supported. Further, it goes without saying that they may be used in combination with other materials such as carbon black and ferrite.

[0020]

As described above, in the dielectric material of the present invention, the dielectric characteristics can be arbitrarily adjusted from a low value to a high value depending on the chemical structure and the filling amount of the surfactant. Further, it can be supported on a solid adsorbent to impart heat resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H01Q 17/00 9067-5J H05K 9/00 M 7128-4E W 7128-4E

Claims (3)

[Claims] 1. A surfactant having at least one of a quaternary ammonium salt group, a hydroxyl group, a sulfonate group, an acid amide group, a carboxylate group and a phosphate group as a functional group, and a dispersion for dispersing and holding the surfactant. A dielectric material consisting of a medium. 2. A solid adsorbent, and at least a quaternary ammonium base as a functional group, which is supported on the solid adsorbent,
A dielectric material comprising a surfactant having any one of a hydroxyl group, a sulfonate group, an acid amide group, a carboxylate group, and a phosphate group, and a dispersion medium for holding these in a dispersed manner. 3. The dielectric material according to claim 2, wherein the solid adsorbent is either zeolite or activated carbon.