JPH0770414B2 - Method of manufacturing film capacitor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip-type film capacitor mainly used in electronic devices and electric devices.

Conventional Technology Conventional capacitors are made of polyphenylene sulfide (PP
A vapor deposition electrode made of aluminum is formed on both sides of a dielectric film made of S), and a coating dielectric made of polyphenylene oxide (hereinafter abbreviated as PPO) is formed on it, cut into a predetermined size, and vapor-deposited on both sides. After making a double-sided coating film, then stacking hundreds of double-sided vapor-deposited double-sided coating films, forming a methacholine layer made of zinc to obtain an electrical connection to the vapor deposition electrode and forming a mother capacitor, and then 90 ° C to 120 ° C. The temperature is raised to ℃, the residual solvent of the coating dielectric is removed, the temperature is 200 ℃, aging is performed for 1 hour, and the milling is performed to make a capacitor element.
After the comb leads were welded, a mold exterior was made using epoxy resin, and the comb leads were processed to form external electrodes, thus completing the product.

Problems to be Solved by the Invention In recent years, in order to miniaturize and improve the performance of electronic equipment and electric equipment, and further to automate the manufacturing process, electronic and electric parts used in these equipment are becoming smaller, higher performance, and made into chips. The demand is very large.

The conventional chip-type film capacitor uses PPO
Due to the low heat resistance of the coating dielectric made of, the PPO undergoes thermal deformation during soldering, resulting in a decrease in withstand voltage.

An object of the present invention is to prevent reduction in withstand voltage due to thermal deformation of PPO during soldering.

Means for Solving the Problems The present invention applies a heat treatment to a film capacitor element,
By cross-linking O to increase the heat resistance of the capacitor, the deformation of PPO at the time of soldering is prevented, the decrease of withstand voltage is prevented, and the problem is solved.

Action That is, the film capacitor element is heat-treated at a temperature of 140 ° C to 190 ° C for 15 hours to 150 hours to cause a crosslinking reaction of PPO, and gradually the PPO takes on a network structure. It has been found that the value becomes higher and the electric characteristics hardly change. For example, in poly 2,6-dimethyl-1.4-phenylene oxide, which is an example of a polymer compound contained in polyphenylene oxide, the infrared absorption spectrum is analyzed, the absorbance of the methyl group decreases after the heat treatment, and the carbonyl group decreases. It can be confirmed that the methyl groups, which are side chains, are cross-linked by the heat treatment from the fact that the absorption of is newly appeared. As a result, the deformation of PPO during soldering can be prevented, and the withstand voltage of the film capacitor can be prevented from lowering.

Example (Example) An example of the present invention will be described below. 2 μm thick
A vapor deposition electrode made of aluminum with a thickness of 400 Å is formed on both sides of a dielectric film made of PPS, and a thickness of 1 μm is formed on it.
5mm wide formed by forming a coating dielectric consisting of PPO
Long double-sided vapor deposition double-sided coating film, then 500 sheets of the double-sided vapor deposition double-sided coating film are laminated, and a 0.5 mm thick metacholine layer made of zinc is formed on both end faces to make a mother capacitor, then this mother capacitor. 90 capacitors
The temperature was raised from ℃ to 120 ℃ to remove the residual solvent of the coating dielectric, heat treatment was carried out at 160 ℃ for 50 hours, PPO was cross-linked, and then aging was carried out at 200 ℃ for 1 hour to make a capacitor element. Then, after welding the comb leads, a mold exterior was applied using epoxy resin, and the comb leads were processed to obtain capacitors as external electrodes.

(Conventional example) Next, as a conventional example, the mother capacitor obtained in the example
After raising the temperature to 120 ° C to remove the residual solvent in the coating dielectric, aging at 200 ° C for 1 hour, milling it into a capacitor element, welding the comb leads, and then using epoxy resin to mold the exterior. Then, the comb leads were individually separated and processed to obtain capacitors.

Each of the capacitors of the present invention and the conventional example obtained as described above is
The average withstand voltage of the capacitors is shown in Table 1 by changing the time of immersing 100 capacitors each in a solder bath at 260 ° C. As a result, the present invention makes it possible to greatly improve the withstand voltage.

Good results were also obtained under other conditions of the present invention or in wound film capacitors.

However, if the heat treatment condition is 140 ° C for 15 hours or less, 2
When immersed in a solder bath at 60 ° C for 15 seconds, the withstand voltage was 50 V or less and there was no effect due to insufficient crosslinking. 1 at 190 ° C
In the case of 50 hours or more, the withstand voltage was good, but the progress of the crosslinking reaction was excessive and the dielectric loss tangent rapidly increased, causing a problem.

EFFECTS OF THE INVENTION By carrying out a heat treatment for crosslinking polyphenylene oxide according to the present invention, the heat distortion temperature rises, and when this is used for a film capacitor, the withstand voltage can be remarkably improved and the reliability is greatly improved. Being able to achieve this and being able to raise the rated voltage are extremely valuable.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masashi Moriwaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Junji Kojima, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kenji Kuwata, 1006 Kadoma, Kadoma City, Osaka Prefecture (72) Kenji Ishida Osaka 1006 Kadoma, Kadoma-shi, Fuchu Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A film capacitor comprising a film capacitor element formed by winding or laminating a polyphenylene sulfide film, an aluminum vapor deposition electrode, and a coating dielectric of polyphenylene oxide, wherein the polyphenylene oxide is crosslinked by heat treatment. Production method. 2. Temperature from 140 ° C to 190 ° C and time from 15 hours
The method for producing a film capacitor according to claim 1, wherein the heat treatment is performed for 150 hours.