JPS63142624A - Capacitor and manufacture of the same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a capacitor using a plastic film as a dielectric for use in electronic and electrical equipment, and a method for manufacturing the same.

BACKGROUND OF THE INVENTION Metallized plastic film capacitors have excellent reliability in electrical characteristics and are widely used in circuits that require particularly stable electrical characteristics, such as time constant and oscillation circuits of electronic devices and electrical devices. Metallized plastic film capacitors use a vapor-deposited metal film as an electrode, so even if there is an insulation defect in the film, the energy when voltage is applied scatters the vapor-deposited metal film around the defect and restores the insulation properties. However, the withstand voltage level can be recovered to the actual value of the film, that is, it has what is commonly called a self-healing action.

A typical dielectric material for metallized plastic film capacitors is polyethylene terephthalate (PET).
), polypropylene (hereinafter abbreviated as pp), etc.

By vapor-depositing metals onto these excellent capacitor dielectric films, the fields of use of metallized plastic film capacitors are steadily expanding.

On the other hand, in recent years, efforts have been made to make electronic and electrical equipment smaller and more multifunctional, and the electronic components used in these devices are also becoming more chip-based, smaller, and more densely packaged due to advances in packaging technology. This trend is also spreading to metallized plastic film capacitors. However, high-density packaging due to chipping and miniaturization means that the capacitor body is exposed to high temperatures when mounting the capacitor, and conventional plastic films such as PET and PP have a high thermal shrinkage rate. Dimensional changes, etc. occur in the electrical characteristics.

This resulted in a significant decrease in reliability. Furthermore, with the miniaturization of electronic and electrical equipment, the internal temperature of the equipment during actual operation is increasing due to high-density packaging, and the metallized plastic film capacitors used in these devices have a maximum operating temperature of 86% higher than the conventional maximum operating temperature.
℃ design is not sufficient, +126°C to +150°C design is now required, and a new plastic film material with excellent heat resistance has been desired.

Recently, polyphenylene sulfide film (hereinafter referred to as PPS) has been developed as a heat-resistant dielectric film material.
Heat resistance is significantly improved compared to PET and PP films,
Moreover, since they have excellent electrical properties, which is one of the major characteristics of film capacitors, they are now attracting attention as a product that can improve heat resistance by making chips, miniaturizing, and high-density packaging of the metallized plastic film capacitors mentioned above.

Problems to be Solved by the Invention However, due to the manufacturing method of PPS, PE
T, compared to PP, there are large amounts of impurities in the polymer (e.g.
(chlorine, sodium, calcium, etc.), and as a result, when used as a dielectric in metallized plastic film capacitors, the self-healing properties characteristic of metallized plastic film capacitors may be impaired due to the influence of the impurities. They are inferior to metallized plastic film capacitors such as PET and PP, and as a result, there are major problems in that insulation resistance and withstand voltage levels are lowered.

In view of the above-mentioned drawbacks, the present invention uses pps as the dielectric material of the metallized plastic film capacitor, and in order to significantly improve the self-healing property, which is the most important feature of the metallized plastic film capacitor, it reduces insulation resistance and withstand voltage. The purpose is to provide a metallized pps film capacitor with high heat resistance, high performance, and high reliability by improving the level drop.

Means for Solving the Problems In order to achieve this object, the capacitor of the present invention defines an average surface roughness Ra of the PPS film that is its dielectric. That is, the average surface roughness Ra of the PPS film was set in the range of 0.03 μm to 0.07 μm, and in the heat press process for flat molding, a combination of elastic rubber and a flat plate that applied pressure only to the flat surface of the capacitor element was used. , and further molding conditions such that the pressure is 5Kg/crl to 10Kg/crl per unit area.
, temperature 1001. ~110C.

It consists of molding for 5 to 15 minutes.

Function The function of the metallized PPS film capacitor with this configuration will be explained below.

As mentioned above, metallized film capacitors have an excellent structural feature of self-healing.

In order to effectively perform this self-healing property, it is necessary to make the vapor-deposited metal film formed on the surface of the film as thin as possible (the resistance of the vapor-deposited film becomes high). The condition of the capacitor is determined by the uniformity of the heat pumpless molding process used to form the flat capacitor element. In other words, by minimizing wrinkles, scratches, or mechanical distortion of the film during heat pumpless molding, thermal and mechanical damage to the film itself can be suppressed, and the gaps and adhesion between film layers can be made uniform. It is necessary to stably release heat, gas, etc. generated by the energy generated when the vapor-deposited metal film scatters out of the capacitor element body.

If the average surface roughness Ra of the PPS film is very small, wrinkles or mechanical distortions are likely to occur during heat press molding where the friction between the PPS film layers is large, and this will reduce the electrical properties. As a result, the heat press molding conditions must be made very weak, and the mechanical stability after deformation tends to vary.

On the other hand, when the average surface roughness Ra is very large, the friction between the PPS film layers is small and the heat press molding distortion is reduced.
Although a uniform molding state can be obtained, in the process after molding,
If a force is applied perpendicular to the pressure of heat press molding, it will easily return to the state before heat press molding, resulting in mechanical instability. It grows without being able to secure the characteristics.

Furthermore, by further increasing the molding conditions and increasing the mechanical molding strength,
Thermal 1 Mechanical damage to the film itself.

This results in stress, which also deteriorates the electrical characteristics.

Based on experimental results from various angles, the present inventors found that in order to eliminate these drawbacks, the average surface roughness R of the PPS film
a needs to be in the range of 0.03 to 0.07 μm,
The heat press molding conditions at that time were as follows: pressure per unit area: 10 Ky/ca * R degree: 100 to 110
It was confirmed that under the conditions of 2 hours and 5 to 15 minutes at °C, no distortion occurred and the mechanical stability and restorability were good.

Furthermore, in the heat press molding process for forming flat capacitor elements, two
When placing a large number of capacitor elements between two hot plates and molding them by applying pressure and heating, it is very difficult to apply uniform pressure due to variations in the capacitor element dimensions and irregularities in the parallelism of the upper and lower hot plates. Because of this, it is difficult to
When a flat plate of elastic rubber that applies pressure only to the flat surface of the capacitor element is combined between two heat plates incorporating an electric heater, variations in the capacitor element dimensions,
They discovered that uniform heat press molding with less variation can be achieved by absorbing the parallelism of the upper and lower hot plates with elastic rubber.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of a capacitor in one embodiment of the present invention. In Fig. 1, 1 is a PPS whose average surface roughness Ra is set to 0.03 μm to 0-07 μm.
The film, 2 is a vapor-deposited metal film formed on the surface of the PPS film 10, and 3 is an electrode extension part formed by metal spraying, from which a voltage is applied.

Figure 2 shows a characteristic diagram. @2 Figure A shows the capacitor element distortion occurrence rate. The horizontal axis shows the average surface roughness Ra, and the M axis shows the molding strain occurrence rate. The molding strain generation rate is the generation rate of film wrinkles and mechanical strain that occur inside the element due to heat press molding. The Toichido breath molding conditions at this time were pressure 6.
K9/CIIK, temperature 100°C, time 5 minutes.

In Figure 2A, the average surface roughness of the film is 0.02
When the thickness becomes less than μm, the strain occurrence rate rapidly increases. This is because the friction between the PPS films constituting the capacitor element increases and there is no mutual slippage.

When the average surface roughness Ra becomes 0.03 μm or more, the molding strain occurrence rate decreases and becomes favorable. This is because as the average surface roughness increases, the friction between the films having a large surface area decreases.

FIG. 2B shows the heat press seismic strength of the capacitor element. The horizontal axis represents the average surface roughness and the vertical axis represents the restoring force. The restoring force is the value obtained by applying a force in a direction perpendicular to the pressure applied during heat press molding after heat press molding. Therefore, it can be said that the larger the restoring force value after heat press molding, the more stable the mechanical strength. The heat press molding conditions at this time are pressure 5? /cIIK+temperature 100°C, time 5 minutes. In Fig. 2B, when the average surface roughness Ra of the film is 0.07 μm, it shows a relatively large value at 2 kg or more, but when the average surface roughness Ra becomes 0.08 μm or more, the value rapidly decreases. I know what will happen.

Since there is a step in which a force in the restoring direction is applied in the steps after heat press molding, the restoring force value needs to be 2 or more. If -2 becomes 9 or less, the element returns due to force being applied in the restoring direction.

From the above, the average surface roughness Ra of PPS film suitable for heat press molding is 0. o3
It is necessary to range from μm to 0.07 μm.

The following table shows the heat press molding conditions (pressure) of the element.

It shows the temperature (1 hour) and molding strength and restoring force).

PPS film average surface roughness Ra o, oa ~0.0
In the range of 7 μm, the condition for the restoring force to be 2 to 2 or more is a pressure of 5 Kg/cI! , the temperature was 100°C for 1 hour and 6 minutes.

Figure 2C shows the heat press molding conditions (pressure) of the element.

This is a diagram showing the relationship between the capacitor boost breakdown value and the temperature (1 hour) and the capacitor pressure breakdown value.
．． In the range of 0.7 μm, pressure 6 to 9/ctA to 10
It can be seen that the boost breakdown level of the capacitor is stable if the temperature is within the range of K9 /al + temperature 100° C. to 110° C. 1 hour 6 minutes to 15 minutes.

FIG. 3 is a configuration diagram showing a state of heat press molding for molding into a flat capacitor element.

FIG. 3A shows an embodiment of the present invention, where 4 and 4' are hot plates incorporating electric heaters, 6 is a capacitor element, 6 is elastic rubber, and 7 is a flat plate such as an iron plate. In the heat press molding method configured as described above, uniform heat press molding with little variation can be obtained by absorbing variations in capacitor element dimensions and parallel accuracy of the upper and lower hot plates with the elastic rubber 3. That will happen.

Figure 3B shows a conventional example, where 4 and 4' are iron plates incorporating electric heaters, and ε is a capacitor element.With this configuration, it is extremely difficult to apply uniform pressure. Needless to say.

FIG. 4 is a diagram comparing the capacitance distribution after hild breath molding of the heat press molding method of the present invention and the conventional heat press molding method.The capacitance of the heat press molding method of the present invention is There is little variation, and there are clear differences between the two.

Effects of the Invention As described above, the present invention provides a capacitor using PPS as a dielectric material of a metallized plastic film capacitor by setting the average surface roughness Ra of the PPS film in the range of 0.03 μm to 0.07/jm. The most important feature of metallized plastic film capacitors, self-healing, can be greatly improved, reducing insulation resistance and withstanding voltage levels, resulting in high heat resistance, high performance,
A highly reliable metallized PPS film capacitor can be provided.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a capacitor according to an embodiment of the present invention, FIG. 2A is a characteristic diagram showing the average surface roughness transformation and capacitor element strain occurrence rate of the present invention, and FIG. 2B is a diagram showing the average surface roughness of the present invention. A characteristic diagram showing roughness Ra and capacitor heat press molding strength, Figure 2C is a characteristic diagram showing the heat press molding conditions of the present invention and capacitor pressure increase destruction value, and Figure 3A is a characteristic diagram showing the heat press molding state of the present invention. FIG. 3B is a configuration diagram showing the conventional heat press molding state, and FIG. 4 is a characteristic diagram comparing the capacitance distribution after heat pressing between the present invention and the conventional heat press molding method. . DESCRIPTION OF SYMBOLS 1...PPS film, 2...Vapour-deposited metal film, 3...Electrode extension part, 4, 4'...
...Hot plate, 6...Capacitor element, 6...
... Elastic rubber, 7... Flat plate. Name of agent: Patent attorney Toshio Nakao and 1 other person/=
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Claims (4)

[Claims] (1) Average surface roughness Ra of 0.03 μm to 0.07 μm
A metallized film is formed by forming electrodes on the surface of a polyphenylene sulfide film having a temperature within the range of 100 to 1000, and a capacitor is constructed from this metalized film. (2) Average surface roughness Ra of 0.03 μm to 0.07 μm
1. A method for manufacturing a capacitor, which comprises: forming an electrode on the surface of a polyphenylene sulfide film having a polyphenylene sulfide film having a range of 100 to 1000 ml, winding this metallized film to form a capacitor element, and then heat-press molding the film. (3) In the heat press molding process, elastic rubber is used in combination with a flat plate that applies pressure only to the flat surface of the capacitor element.
2. Method for manufacturing the capacitor described in section. (4) A patent characterized in that in the heat press molding process, the pressure is 5 Kg/cm^2 to 10 Kg/cm^2 per unit area, the temperature is 100°C to 110°C, and the time is 5 to 15 minutes. A method for manufacturing a capacitor according to claim 2.