JPH0461705A - Highpolymer composite dielectric substance - Google Patents

Abstract

PURPOSE:To provide a highpolymer composite dielectric substance having a high dielectric factor without impairing the processing easiness and without increasing the filling rate of filler by dispersing a specific powder of dielectric substance as a filler in a matrix consisting of highpolymer resin. CONSTITUTION:A powder of dielectric substance having the max particle size between 10-500mum is dispersed as a filler in a matrix 2 consisting of highpolymer resin. This yields a highpolymer composite dielectric substance having a larger dielectric factor than the case where filling is made with particles of smaller max. particle sizes with the same volume ratio. This allows provision of high dielectric factor and enables performance of injection molding or the like, so that even a complex configuration can be fabricated through simple manufacture processes.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polymer composite dielectric material used in capacitors and the like.

<Conventional technology> Plastics such as polyester and polypropylene are
It has also been used as a dielectric material for capacitors and other devices. However, the dielectric constant of most plastics is around 5. Therefore, increasing the dielectric constant of plastics is being studied in various fields in order to accommodate applications such as capacitors and filters that require a high dielectric constant. One such method is to disperse ceramic powder or fiber as a filler in a plastic matrix. That is, the dielectricity of plastics has been increased by increasing the filler filling rate or by further increasing the dielectric constant of the filler. Furthermore, it has been thought that the shape of the filler should be as fine as possible in order to improve dispersibility.

<Problems to be Solved by the Invention> When a plastic is filled with a cetemix filler having a high dielectric constant, the dielectric constant of the plastic can be improved as the filling rate is increased. However, if the filling rate is increased, the inherent properties of the resin will be impaired, resulting in a problem in that the molding method will be limited. The dielectric constant can also be improved by increasing the dielectric constant of the filler, but the dielectric constant is a value specific to the material, and the maximum value for currently commercially available products is about 10,000, which is a limit. It is occurring.

In view of the above-mentioned problems, the present invention aims to provide a high dielectric constant polymer composite dielectric material that can be produced without losing workability or increasing the filling rate of ceramic filler.

Means to solve problems〉 An explanation will be given based on drawings that are perspective views of embodiments of the present invention.

The polymer composite dielectric of the present invention has a maximum particle size of 10 to 50
It is characterized in that dielectric powder having a diameter of 0 μm is dispersed as a filler 1 in a matrix 2 made of a polymer resin. Further, the dielectric powder is made of at least one of a perovskite compound represented by A B Os and titanium dioxide, and the dielectric powder has a dielectric constant of 50 or more at room temperature.

Effect〉 By filling resin with dielectric particles with a maximum particle size of 10 to 500 μm, a polymer composite dielectric with a larger dielectric constant can be produced than when filling resin with particles with a small maximum particle size at the same volume ratio. can get. Further, a perovskite compound represented by ABO2, for example, barium titanate, is a ferroelectric substance, and piezoelectricity can be imparted by polarizing the composite. Titanium dioxide also has a high dielectric constant. Therefore, a polymer composite dielectric material in which a filler consisting of a perovskite compound represented by ABO and at least one of titanium dioxide is dispersed has a high dielectric constant.

Further, a polymer composite dielectric material prepared by dispersing a filler having the above-mentioned characteristics and having a dielectric constant of 50 or more at room temperature becomes a dielectric material having an even higher dielectric constant.

<Embodiment> The figure is a perspective view of an embodiment of the present invention. The polymer composite dielectric material of the embodiment of the present invention has a matrix 2 made of polymer resin.
Filler 1 made of dielectric particles is dispersed therein.

A method for producing a polymer composite dielectric according to an example of the present invention having the above configuration will be described below, and the results of calculating the dielectric constant of the obtained polymer composite dielectric will be shown.

1) Creation of ceramic powder (P bo, *1Sro, as) (Tio, 4s・Z
ro, 54) Weigh the oxide of each element so that it becomes Os,
The mixture is calcined (850°C). Thereafter, after crushing and shaping, it is fired (1250° C.) to create a PZT sintered body of 20φ×11. The dielectric constant of one sheet of the above-mentioned PZT sintered body is about 1300. Next, this sintered body is
Pulverized for 3 hours in an alumina pot containing 0φ alumina balls, 0.9 μm or less, 1 to 9.9 μm S 10 to
45μm146~100μmS101~150. czm
, 151-212 μm.

The range of 213 to 300 μm is classified into 50 μm widths, and the powder of 300 μm or more is crushed and classified again to create filler 1 of ceramic powder of each size. 2
) Compositeization is performed by dispersing filler 1 of the above-mentioned particle type in matrix 2 to create the polymer composite dielectric of the present invention.

That is, 7.5 g of dibutyltin malate as a stabilizer.
, 4g polyethylene wax 1 1 vinyl chloride resin to which 2g stearic acid monoglyceride was added as a lubricant
50 g of PZT powder of each size prepared by the above method is weighed and mixed at a ratio of 30 vol. Next, the mixture is kneaded for 5 minutes using rolls with a surface temperature of 165°C to form a sheet. This sheet is cut into predetermined dimensions and hot pressed at a temperature of 170° C. to produce a plate with a thickness of 2 mm.

3) A 2 mm thick polymeric dielectric plate prepared by the method described above is cut into 50 mm x 50 mm pieces, and aluminum electrodes are formed by vacuum evaporation.

This test piece was measured using a Gain Seize Analyzer (419 manufactured by YHP).
4A, measurement frequency IMHz), and the dielectric constant calculated from the electrode area and electrode spacing is shown in the table.

From the above results, the dielectric constant of the example of the present invention is higher than that of the comparative example in which ceramic powder particles having a diameter of less than 10 are composited. That is, the maximum particle size is 10~
By filling the resin with ceramic powder of 500 μm, a larger dielectric constant can be obtained than when filling the resin with powder having a small particle size at the same volume ratio. Also, the reason why the maximum particle size is limited to 10 to 500 μm is that even if it is made larger than this, the increase in dielectric constant will be small, and if a large size filler 1 is added, the moldability of the resin and the smoothness of the surface will deteriorate. It's for a reason. The practical limit is 500 μm. The dimension of this powder refers to the dimension in the longest direction of the particle, and also includes fiber shapes with an aspect ratio of less than 5. Further, it is the average size of the powder that accounts for the majority of the filler 1 dispersed in the resin, and 100% does not necessarily have to be within this range.

The ceramic powder applied to the present invention is a perovskite compound represented by titanium oxide and AB Os,
That is, barium titanate, lead titanate, lead zirconium titanate, etc., and some or all of the A site and B site of these perovskite compounds can be replaced with strontium, magnesium, calcium, tin, niobium, lanthanum, antimony, etc. At least one element such as cobalt is substituted. The present invention uses one or more of these materials for the filler 1, and is not limited to the above materials.

Also, since large particles have a smaller surface area than fine particles,
It is relatively easy to increase the filling factor, and a polymer composite dielectric with a high dielectric constant can be formed.

The resins applied to the embodiments of the present invention include thermoplastic resins such as vinyl chloride, polybutylene terephthalate, and polycarbonate, and thermosetting resins such as epoxy, but are not limited to those currently commercially available. All resins are applicable and can be selected depending on the application based on the required strength, weather resistance, and electrical performance such as dielectric loss.

In addition, stabilizers, lubricants, reaction accelerators, and reinforcing fibers such as glass fibers may be used in combination with these resins, if necessary.

Further, the kneading and molding of the composite dielectric material of the embodiments of the present invention can be performed by extrusion molding, injection molding, direct mixing molding using calender rolls, etc., but is limited to these methods, such as using other mixing methods in combination. You can choose based on the shape of the product, type of resin, etc.

<Effects of the Invention> As described above, the polymer composite dielectric material according to the present invention has the following effects:
Since the filler with the optimum particle size determined from the relationship between the electric field strength dispersed in the matrix and applied to the T-ceramic powder and the particle size is used, a high dielectric constant can be achieved by filling a small amount of filler. In addition, injection molding is also possible, so even complex shapes can be manufactured using simple manufacturing processes.

As a result, since the polymer composite dielectric material according to the present invention has a larger dielectric constant than conventional resins, a compact and high-performance capacitor can be obtained.

[Brief explanation of drawings]

The figure is a perspective view of an embodiment of the present invention. 1... filler 2...Matrix resin

Claims (3)

[Claims] (1) A polymer composite dielectric material in which dielectric powder having a maximum particle size of 10 to 500 μm is dispersed as a filler in a matrix made of a polymer resin. (2) The polymer composite dielectric material according to claim 1, wherein the dielectric powder comprises at least one of a perovskite compound represented by ABO_3 and titanium dioxide. (3) The polymer composite dielectric according to claims 1 and 2, wherein the dielectric powder has a dielectric constant of 50 or more at room temperature.