JPH01161817A - Heat resistive film capacitor - Google Patents

Abstract

PURPOSE:To make it possible to perform tip soldering of a capacitor and to improve a high temperature durability, in a metallized film capacitor or a foil-wound film capacitor, by using polyether ether ketone film as a dielectric of the capacitor. CONSTITUTION:Polyether ether ketone, which is a resin of polyether ether ketone film(PEEK film) used as heat resistive film, comprises a straight-chain macromolecule of an aromatic group in which benzene rings are connected with ether and carbonyl groups. The material has excellent radiation resistance, heat resistance, hot water resistance and fire retardancy because of a high content of the benzene rings in the molecule. Such a PEEK film can be applied to non-oriented, monoaxially oriented and biaxially oriented films, among which the biaxially oriented film is desirable. To form a capacitor by using the film, single-size metallized film 3 for which the PEEK film is used as a dielectric is wound so that margins 4 and 4 face to each other, forming a capacitor element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metallized film capacitor and a foil-wound film capacitor, and particularly to a heat-resistant film capacitor using a highly heat-resistant film.

[Prior Art] In recent years, electronic devices and electrical devices have become smaller and smaller, and in printed circuit boards, components such as capacitors are now mounted not only on one side but also on both sides due to higher density mounting methods. In this case, parts such as capacitors are now attached to the board by temporarily fixing them with adhesive or the like and immersing them in a solder bath.

Therefore, components such as capacitors are directly exposed to high temperatures of as high as 260°C in the soldering bath. Especially in the case of metallized film capacitors and foil-wrapped film capacitors, there is no film that can withstand high temperatures. The main method was to limit the part that was immersed in water to only the lead wire.

For example, the melting point of polyester film, which is normally used as a dielectric in film capacitors, is around 260°C, so unless the solder melting temperature is set low at around 230°C during component mounting, the film will heat up even if immersed for a short time. This may cause the capacitor element to become soft or deformed, increasing the defective rate of the capacitor element.

Recently, it has been proposed to use polyphenylene sulfide film as a heat-resistant film in metallized film capacitors (JP-A-62-183105, JP-A-62-203313).
However, the melting point is still 285℃.
Therefore, compared to polyester film, there is only a margin of about 25°C, and it is necessary to keep the temperature of the solder bath low.

Lowering the temperature of the solder bath deteriorates the fluidity of the solder, sacrificing workability and reliability of soldering, and also prevents problems such as blistering of the film due to heat in capacitor elements after mounting. Deformation occurred, and actual damage to the electrical properties such as a decrease in capacitance and connection failures occurred at the metallized parts on the end faces was common.

In recent years, the use of chips in the parts of electronic and electrical equipment has progressed considerably, and in the capacitor field as well, the use of chips has become unavoidable due to advances in automation and labor-saving. Bathtub treatment is required as an essential process.

For this purpose, the film used as the dielectric of the capacitor itself is required to have high heat resistance, and the appearance of a heat-resistant film has been eagerly awaited.

[Problems to be Solved by the Invention] Under these circumstances, it is an object of the present invention to make the dielectric films of metallized film capacitors and foil-wound film capacitors highly heat resistant, so that they can be used in high humidity environments. To provide a heat-resistant film capacitor that overcomes defects caused by film deformation that are a concern in chip soldering, enables chip soldering of a capacitor with just one chip, and has extremely superior high-temperature durability characteristics.

[Means for Solving the Problems 1] The present invention is a metallized film capacitor or a foil-wound film capacitor, in which the 1712 body of the capacitor is made of a polyether ether ketone film.

Polyetheretherketone film (hereinafter abbreviated as PEEK film) used as a heat-resistant film in the present invention
As shown in the structure below, polyetheretherketone, which is the resin of , heat resistance, hot water resistance,
It is known to have excellent flame retardancy.

In particular, the heat-resistant temperature is 350 to 360°C, which is the highest among conventionally used thermoplastic heat-resistant resins.The present invention focuses on this high heat-resistant temperature, and uses it as a dielectric material for heat-resistant film capacitors. It was a success.

In the present invention, film capacitors using a film as a dielectric for P[E are metallized film capacitors and foil-wound film capacitors. When mounting these film capacitors on a printed circuit board, the capacitor element is temporarily attached to the board with adhesive and immersed in a solder bath at a temperature of around 260°C, but with conventional polyester film, which has a melting point of around 250°C, only the lead wires are needed. In the present invention, PEE with a melting point of 350 to 360°C can be used.
By using a film, it is possible to perform reliable soldering at the necessary and sufficient solder bath temperature, and metallized film capacitors and foil-wound film capacitors with excellent electrical properties can be produced.

Furthermore, in the production of metallized film capacitors or foil-wound film capacitors, the present invention provides that when a polyetheretherketone film is used as the dielectric of the capacitor, the melting point of the PEEK film is 35% as described above.
Since the temperature range is from 0 to 360°C, it is possible to raise the temperature of the heat press of the capacitor element to about 300°C, as well as the 260°C of the solder bath.

An appropriate heat press temperature range is set within a range in which the electrical characteristics of the capacitor can be stably obtained.

As mentioned above, in order to prevent troubles caused by deformation of the film that occurs when the capacitor element is immersed in a solder bath at high temperatures, the present invention uses a PEEK film, but this manufacturing method uses a film for PEE. As a result, heat setting is performed at a high temperature that is close to the heat press temperature during capacitor element manufacturing to the temperature applied during the mounting process. Generally speaking, the upper limit of the heat press temperature for film capacitors based on polypropylene (PP) film is around 120°C, and for film capacitors based on polyester (PET) film, around 180°C.

This means that the melting point of the film is approximately 160°C for PP film, and
This is because the temperature of the E-film is about 260°C, and it is impossible to heat set the solder bath at a temperature of around 260°C due to the nature of the film.

In addition, polyphenylene sulfide (
Even PPS) film has a melting point of 285°C, so it is practically difficult to heat press it at a temperature around 260°C. The absolute condition for enabling heat pressing at a temperature around 260°C is to have a melting point of at least 300°C or higher, and this is where the significance of using a film for PEE in the present invention lies.

Incidentally, the physical properties of the PIE film (biaxially stretched) are shown in Table 1 and compared with the conventionally commonly used PET film.The PEE film has a melting point of 350°C, which fully satisfies the temperature conditions mentioned above. This makes it possible to obtain heat-resistant film capacitors of industrially stable quality.

Furthermore, P[EK films include unstretched films, uniaxially stretched films, and biaxially stretched films, but biaxially stretched films can be made thinner (a) than other films. A small film with a thickness of 0 can be produced. V ~ 2 as a dielectric material for capacitors due to its excellent strength and withstand voltage.
Axially stretched PE film is superior.

In the present invention, the film is unstretched, uniaxially stretched, 2
Although axial stretching can also be used, biaxially stretched film is preferred for the above reasons.

Table 1 [Examples] Next, the present invention will be explained in more detail by way of Examples with reference to the drawings.

FIG. 1 is a partially enlarged cross-sectional view showing the structure of the metallized film capacitor of the present invention.

First, metal aluminum was deposited on one side of the film 1 on biaxially stretched PEE with a thickness of 3.7 μm using a continuous vacuum deposition machine in a conventional manner to form a metallized film 3, and a single-sided metallized film 3 was obtained. I gave up. The width of margin 4 at this time is 1.5 m + 1 The resistance value of the metal vapor deposited film is 2.0
It was Ω/mouth.

As shown in FIG. 1, a single-sided metallized film 3.3 using the film as a dielectric was wound around PEE with the margins 4.4 facing each other to obtain a capacitor element with a capacitance of 3 μF.

For comparison, a 3.8 μm thick PET film was deposited in the same manner as in the example and wound to obtain a capacitor element with the same capacity. For each, heat press conditions of 150°C and 180°C, which is higher than that normally used for PET film, were applied.
℃, 200℃, and 240℃.

The pressing pressure was 30'J/ci and the pressing time was 10 minutes. The end faces of the thus obtained heat-pressed elements were coated with metallicon by melting zinc particles to evaluate their heat resistance as capacitors.

For heat resistance evaluation, each element sample obtained above was placed in a hot air circulation thermostat, left at each temperature of 180 to 280°C for 10 minutes, and then taken out to observe changes in capacitance. The results are shown in FIG.

According to FIG. 2, even when heat set at 180° C., the PE film is superior to the PET film because the rate of change in capacitance is smaller. Heat press temperature is pudding]
- Bringing the heat press temperature close to the solder melting temperature when it is mounted on a wiring board, etc. will reduce the deformation of the film due to heat, but by using a film for PEE, it is possible to bring the heat press temperature close to the solder melting temperature. I can do it,
We were able to obtain a capacitor with excellent thermal stability, which was not previously possible.

AC durability test In the production of the metallized PEE film and PET film used to measure the capacitance change rate described above, the metallized PEEK film was manufactured in the same manner except that the margin width was 21 m.
A film and a metallized PET film were obtained. Thereafter, winding was carried out in the same manner, and the heat pressing conditions were the same except that the PEE film was heated at 180°C, 308y/ai, 10 minutes, and the PET film was heated at 150°C, 30mm/ai, 10 minutes. Capacitor elements of metallized PEE film and metallized PET film were obtained.

Figures 3 and 4 show the results of applying 60 Hz and 200 V@continuously to these capacitors in an atmosphere of 100°C and 150°C until they were destroyed.

According to Figure 3, the PET film used in an atmosphere of 100°C breaks down in a few hours, but the PEE film of the present invention did not break even after 1000 hours of continuous application. 1. Also, even if the a3 was placed in the 150° C. atmosphere shown in FIG. 4, no destruction occurred even after i ooo hours had elapsed.

Other configuration examples of the heat-resistant film capacitor of the present invention In addition to the configuration of the metallized film capacitor described above, the fifth
An example is given in the figure.

FIG. 5 shows a double-sided metallized film 5 in which an aluminum metal cap@layer 2.2 is provided on both sides of the PEEK film 1 of the present invention.
A partially enlarged cross-sectional view of a capacitor element obtained by winding a film 6 and non-evaporated PEE.

FIG. 6 shows an example of the foil-wound film capacitor of the present invention. FIG. 6 is a partially enlarged cross-sectional view of a capacitor element in which non-evaporated PEEK film 6.6 and aluminum foil 7.7 are wound in alternating layers.

The configurations of the metallized film capacitors and foil-wound film capacitors shown in the drawings are examples, and conventionally known combinations of dielectrics and electrodes can be applied, and the structures are not limited to the illustrated examples.

Including the example of the metallized film capacitor shown in Figure 1 above,
The configuration of the capacitor element shown in each figure is a schematic conceptual diagram; in reality, a specified capacitance is obtained by laminating multiple layers or winding the capacitor multiple times.

Thereafter, after forming the capacitor element by heat pressing, the ends are subjected to metallization by spraying metal particles such as molten zinc or solder to form the capacitor element, as described in the previous embodiment.

[Effect 1 of the Invention] The heat-resistant film capacitor of the present invention has the advantage that with conventional metallized film capacitors and foil-wrapped film capacitors, the temperature of the solder bath cannot be maintained at a sufficient temperature due to the limitations of the heat resistance of the film used as a dielectric material. We used polyether ether ketone film as the heat-resistant film to solve problems such as not being able to perform proper soldering or poor rate of change in capacitance n due to film deformation. By increasing the heat press temperature during manufacturing, it is possible to achieve reliable soldering at a sufficient temperature in the soldering bath, and it also eliminates problems such as film deformation. It was possible to significantly improve the durability characteristics of the steel.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged cross-sectional view showing the concept of the element of the metallized film capacitor of the present invention, and Fig. 2 shows the heating temperature and capacitance change rate of the metallized film capacitors of the example of the present invention and the comparative example. A graph showing the relationship, Figure 3 is a graph showing the AC durability test results in a 100'C atmosphere for metallized film capacitors of Examples and Comparative Examples of the present invention, and Figure 4 is the same.
A graph showing the results of an AC durability test at 50°C, Fig. 5 is a partially enlarged cross-sectional view showing another example of the metallized film capacitor of the present invention, and Fig. 6 is a portion showing an example of the foil-wrapped film capacitor of the present invention. It is an enlarged cross-sectional view. 1...PEEK film, 2...Metal steamer, 3.
・・Single side metallized film, 4・margin, 5・・
double-sided metallized) film, 6... non-evaporated PEEK film, 7... aluminum foil. Patent applicant Honshu Paper Co., Ltd.

Claims (1)

[Scope of Claims] 1. A heat-resistant film capacitor, which is a metallized film capacitor or a foil-wound film capacitor, characterized in that the dielectric of the capacitor is made of a polyetheretherketone film. 2. The heat-resistant film capacitor according to claim 1, wherein the polyetheretherketone film is an unstretched film. 3. The heat-resistant film capacitor according to claim 1, wherein the polyetheretherketone film is a uniaxially stretched film. 4. The heat-resistant film capacitor according to claim 1, wherein the polyetheretherketone film is a biaxially stretched film.