JPH0448506A - Dielectric composite for film capacitor - Google Patents

Abstract

PURPOSE:To hold flexibility and a good insulating property by making Si urethane resin having siloxane coupling in a main chain contain a specific wt.% of inorganic ferroelectrics. CONSTITUTION:By making silicon urethane resin having siloxane coupling in a main chain contain 50 to 90wt.% of inorganic ferroelectrics or inorganic high dielectrics, a film capacitor is obtained without being damaged in flexibility while sufficiently maintaining an insulating property.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a dielectric composition for a film capacitor used in a film capacitor, and more specifically, a dielectric composition for a film capacitor that is composed of a resin base material and a ferroelectric compound or a high dielectric material. Among the components of the dielectric composition for film capacitors, which consists of a dielectric composition for film capacitors, the insulation properties of the resulting film capacitors are particularly improved by improving the resin base material from the viewpoint of the physical properties of the film. The present invention relates to a dielectric composition for film capacitors that can be increased.

[Conventional technology] Conventionally, dielectric films for film capacitors include:
1, a dielectric constant of about 2 to 5 is widely used, and inorganic ferroelectric materials such as barium titanate or titanium dioxide, etc. are used to increase the dielectric constant of films mainly made of resin base materials. A film in which an inorganic high dielectric material is mixed is being considered.

For example, Special Publication No. 59-15340 and Special Publication No. 59-15340 and Special Publication No. 59-15340
No. 15341 discloses a high dielectric constant film comprising a single layer or multiple layers of a thermoplastic polymer film containing a ferroelectric material blend such as calcium titanate.

In addition, Japanese Patent Publication No. 5246/1983 discloses that a layer containing a ferroelectric material is used for the purpose of improving the stretching defects of a film consisting only of a layer containing a ferroelectric material and providing a composite film that exhibits an excellent high dielectric constant. and a thermoplastic polymer layer containing a ferroelectric material such that the average content of the total film after lamination is 15% by weight or more with respect to the total film. A biaxially stretched high dielectric constant composite film is disclosed.

Other combinations of a film base material and a ferroelectric compound or a high dielectric compound include, for example, Japanese Patent Application Laid-open No. 60-17010.
No. 3 contains inorganic powder with a dielectric constant of 100 or more in a plastic binder with a dielectric constant of 14 or more at 10 to 90 Vo.
A capacitor using a composite containing 1% as a dielectric is disclosed, and JP-A No. 64-25406 discloses a method in which an inorganic ferroelectric powder is added to a polymeric liquid crystal compound that forms an optically anisotropic melt phase. A mixed and formed capacitor film is disclosed.

Furthermore, we used polyphenylene oxide as the film base material and surface-treated fl fine particle titanium oxide as a high dielectric material, and by surface treatment of the high dielectric material, we improved the adhesion with plastic materials and imparted surface hydrophobicity. Film capacitors that can suppress capacitance changes due to moisture absorption without deteriorating electrical characteristics such as withstand voltage and dielectric loss tangent are disclosed in Japanese Patent Application Laid-Open No. 1-130514 and Japanese Patent Application Laid-open No. 1-130514.
-130515 and JP-A-1-130516.

However, these conventional techniques related to film capacitors mainly aim at increasing capacitance, that is, increasing dielectric constant, and focus on improving performance from this perspective. Therefore, among the components of a dielectric composition for film capacitors consisting of a resin base material and a ferroelectric compound or a high dielectric compound, improvements have been made focusing on the ferroelectric compound or the high dielectric compound. However, there have been few attempts to improve capacitor performance from a comprehensive perspective by focusing on resin-based base materials.

There are limits to improvements that focus primarily on ferroelectric compounds or high dielectric compounds, and for this reason, especially when inorganic ferroelectrics are included, the flexibility of the film itself is impaired, making it difficult to form into capacitors. Detracting flaws,
There was a drawback that insulation properties deteriorated. In order to solve this problem, there is a method of using a composite film with a laminated top layer as described in the above-mentioned Japanese Patent Publication No. 61-5246, but it is possible to achieve the objective by using a simpler single-layer #l film. If this can be achieved, it would be desirable from the perspective of industrial production.

[Problem U to be Solved by the Invention] The present invention focuses on the physical properties of the film among the components of a dielectric composition for a film capacitor consisting of a resin base material and a ferroelectric compound or a high dielectric compound. Provides a dielectric composition for a film capacitor that provides a film capacitor that can maintain sufficient insulation properties without impairing the flexibility of the film, by improving the resin base material from the viewpoint of The purpose is to

[Means for Solving the Problems] According to the present invention, the raw bait is characterized in that the silicone-based urethane resin having a siloxane bond contains 50 to 90% by weight of an inorganic ferroelectric material or an inorganic high dielectric material. A dielectric composition for a film capacitor is provided.

It is preferable that the inorganic ferroelectric material is barium titanate.

It is preferable that the inorganic high dielectric material is titanium dioxide.

[Effect]

In general, when a film contains an inorganic ferroelectric material, its insulation properties decrease, but this phenomenon is thought to be caused by the current flowing on the surface of the inorganic material due to poor adhesion between the film and the inorganic material. .

In the present invention, among the components of a dielectric composition for a film capacitor consisting of a resin base material and a ferroelectric compound or a high dielectric compound, the resin base material is particularly selected from the viewpoint of the physical properties of the film. We made improvements focusing on the material, using a silicone urethane resin with a siloxane bond in the main chain that has high adhesion to inorganic materials, and containing 50 to 90% by weight of an inorganic ferroelectric material or an inorganic high dielectric material.

By using the silicone-based urethane resin of the present invention as the base material of the film, the adhesion with inorganic substances is greatly improved.
It exhibits excellent insulation properties even when the amount of compounds such as barium titanate is increased compared to conventional films.

[Effects of the Invention] According to the present invention, among the components of a dielectric composition for a film capacitor consisting of a resin base material and a ferroelectric compound or a high dielectric compound, particularly from the viewpoint of the physical properties of the film, We made improvements focusing on the resin base material, using a silicone urethane resin with a siloxane bond in the main chain that has high adhesion to inorganic materials, and adding 50 to 90% by weight of an inorganic ferroelectric material or an inorganic high dielectric material to this resin. There is provided a dielectric composition for a film capacitor that provides a film capacitor that can sufficiently maintain insulation properties without impairing the flexibility of the film.

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited only to the following Examples.

R-305 (Shin-Etsu Silicone) is used as the silicone urethane resin, and barium titanate (Ba
FIG. 1 shows the relationship between the content rate and relative dielectric constant when Ti0sl is contained.

From FIG. 1, it can be seen that as the barium titanate content increases, the relative dielectric constant increases. On this occasion,
Since the relative permittivity increases significantly when the barium titanate content exceeds 50%, it is necessary to contain barium titanate in an amount higher than this level.

In conventional resin-based base materials, when inorganic ferroelectric materials such as barium titanate were contained in high concentrations, the physical properties of the film deteriorated significantly, but this was not the case with the silicon-based urethane resin used in the film of this invention. Therefore, even if it is contained at a high concentration, such a decrease in physical properties does not occur, and the flexibility of the film is maintained.

A dielectric composition for film capacitors containing 57% barium titanate (BaTi0i) in Shin-Etsu Silicon KR-305 (silicon-based urethane varnish) resin was prepared, and a film was prepared using this in a conventional manner. Manufactured capacitors.

A dielectric composition for film capacitors containing 89% of barium titanate (BaTi0i) in R-305 (silicon-based urethane varnish) resin was manufactured using Shin-Etsu Silicon, and using this, a conventional method was used. A film was prepared using the method described above, and a film capacitor was manufactured.

Barium titanate (Ba
A dielectric composition for a film capacitor containing 51% of TiOi ) was prepared, and a film was formed using this in a conventional manner to produce a film capacitor.

Comparison ■4 titanium dioxide in polyethylene terephthalate resin
A dielectric composition for a film capacitor containing 7% of the dielectric composition was prepared, and a film was prepared using this in a conventional manner to produce a film capacitor.

A leakage current test was conducted on the films for film capacitors according to Examples 1 and 2 and Comparative Examples 1 and 2.

The leakage current test was conducted using each film sample (area 4C11
2>, the voltage is 4 by a constant voltage power supply.

Leakage t? 1 minute after applying a pressure of 50V? This was done by measuring the L value. The results are shown in Table 1.

Thickness of tombstone film Leakage current L1 - Construction Example 1 19.3 1.1 Example 2
39.5 0.7 Comparative Example 1 19.8
98.4 Comparative Example 2 20.6 10
From the results of 9.6 and above, it can be seen that the dielectric composition for a film capacitor according to the present invention provides a film capacitor that can maintain sufficient insulation properties without impairing the flexibility of the film.

[Brief explanation of the drawing]

Figure 1 shows KR-305 as a silicone urethane resin.
(Shin-Etsu Silicone) is used and barium titanate (8aTi03) is contained in this resin. It is a diagram showing the gap between the content rate and the relative dielectric constant.

Claims (3)

[Claims] (1) Add 50 to 50% of inorganic ferroelectric material or inorganic high dielectric material to silicone urethane resin having siloxane bonds in the main chain.
A dielectric composition for a film capacitor, characterized in that it contains 90% by weight. (2) Claim 1 wherein the inorganic ferroelectric material is barium titanate.
The dielectric composition for a film capacitor as described above. (3) The dielectric composition for a film capacitor according to claim 1, wherein the inorganic high dielectric material is titanium dioxide.