JP2000021673A - Metalized film and method therefor, and capacitor using the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film and a capacitor which can improve the press performance and can suppress the capacitor noise by improving the quality of a non-metalized surface of a metalized film for the capacitor. SOLUTION: A metalized film 1, having a margin 4 formed by a metalized layer 3 which is to become an electrode and oil 5 on a single surface of base material made of a polymer film 2, has a surface tension at an opposite surface on which has the metalized layer 3 of the polymer film 2 and the margin 4 of 33 dyne/cm or higher and is set 1 dyne/cm higher than the inherent surface tension of the polymer film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallized film for a capacitor, a method for producing the same, and a capacitor using the same.

[0002]

2. Description of the Related Art Metal-deposited films for capacitors use a tape or apply oil to a margin forming portion to form a margin at the time of vapor deposition so that metal does not adhere to this portion. Of these, metal-deposited films that have a margin using oil have a high dielectric strength voltage due to the adhesion of the vapor-deposited metal powder to the margin generated by the tape-based margin or the jagged edges of the metal-deposited layer at the margin. It is an excellent metal-deposited film with no drop, high withstand voltage and high corona discharge starting voltage.On the other hand, this oil deteriorates the pressability of the element when making the capacitor element, and accordingly the adhesion between the capacitor films When the voltage is applied to the capacitor, the film resonates and emits a sound, which causes a problem called a squeal.

As a method of preventing the squeal phenomenon, US Pat. No. 5,563,763 discloses a method of tightening a capacitor itself, and Japanese Patent Publication No. 3-12447 discloses a method for improving the adhesion of a film. A method has been proposed in which a film coated with a material having good adhesiveness is bonded to a metal-deposited film. However, these methods have the problem of increasing materials and processing steps, increasing cost and increasing the size of the capacitor.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal-deposited film having improved press-fitting property and improved squealing with improved adhesiveness between films.

[0005]

In order to solve the above-mentioned problems, a metal-deposited film for a capacitor according to the present invention is formed by forming a metal-deposited layer serving as an electrode and oil on one surface of a base material made of a polymer film. In the metal-deposited film having a margin portion, the surface tension of the opposite side of the metal-deposited layer of the polymer film and the surface having the margin portion is 33 dyn.
e / cm or more and 1 dyne / cm or more higher than the surface tension inherent to the polymer film.

Further, according to the method of manufacturing a metal-deposited film for a capacitor according to the present invention, a metal-deposited film having a metal-deposited layer serving as an electrode and a margin formed by oil is provided on one surface of a base material made of a polymer film. In manufacturing, in a vacuum deposition machine, before or after metal deposition, or before or after the formation of the margin portion, from the method characterized in that the opposite surface of the surface having a metal deposition layer and the margin portion of the polymer film is subjected to discharge treatment Become.

[0007] A capacitor according to the present invention is formed using the above-described metal-deposited film.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a metal-deposited film for a capacitor according to the present invention, a method for producing the metal-deposited film, and a capacitor using the metal film will be described in more detail with preferred embodiments.

FIG. 1 shows a schematic configuration of a metal-deposited film for a capacitor according to an embodiment of the present invention. Note that the present invention is not limited to this embodiment.

In FIG. 1, reference numeral 1 denotes a metal-deposited film according to the present invention, 2 denotes a substrate made of a polymer film, 3 denotes a metal-deposited layer, 4 denotes whether a metal-deposited layer is not formed, or An insulating portion (hereinafter, referred to as a margin or a margin portion) for maintaining insulation from a counter electrode when the capacitor is formed by an insulating portion formed of a metal oxide or the like. Reference numeral 5 denotes an oil for forming the margin 4. 6
Indicates the surface of the polymer film of the film substrate on which no metal deposition is performed, that is, the surface opposite to the surface having the metal deposition layer 4 and the margin 4.
dyn / cm or more, and 1 dyne / cm or more higher than the surface tension inherent to the polymer film as the base material.

The polymer film referred to in the present invention is a polymer film such as polyolefin such as polypropylene, polystyrene, polyester such as polyethylene terephthalate or polyethylene naphthalate, polyphenylene sulfide, or a copolymer resin thereof. Say what you did.

The metal deposition layer is a metal such as Al, Zn, Sn, Cu or an alloy thereof on a polymer film in a vacuum deposition machine by a melting heating method, an induction heating method, an electron beam method, a sputtering method or the like. It is deposited and becomes a conductive layer to be an electrode in a capacitor.

The margin formed by oil is as follows.
Before providing a metal deposition layer in a vacuum deposition machine, fluorine-based oil, silicone-based oil, or mineral-based oil is deposited on the polymer film to prevent adhesion of the deposited metal,
When a capacitor is formed, an insulating portion provided for insulating the counter electrode is formed. As described above, the margin formed by the oil is an excellent margin for improving the withstand voltage, but on the other hand, the remaining oil hinders the adhesion of the films to each other so that the flat-type capacitor (press-type capacitor) can be formed. Since the pressability is deteriorated and the adhesion between the films is poor, the film is likely to vibrate when an AC voltage is applied to the capacitor, generating a sound, that is, a so-called squeal. In particular, a squeal phenomenon is apt to occur in a cold-press type flat capacitor which is pressed at a low temperature under a strong pressure and formed flat.

The present invention has been made in order to improve the squeal phenomenon in particular. The surface opposite to the surface having the polymer film deposited layer and the margin portion is surface-modified to have a surface tension of 33 dyne. / Cm or more and 1 dyne / cm or more higher than the intrinsic surface tension of the polymer film. The polymer film has a specific surface tension, for example, 32 dy for polypropylene.
ne / cm, 42 for polyethylene terephthalate
Although it has a surface tension of dyne / cm, in the present invention, the surface tension is increased by 1 dyne / cm or more by surface modification. More preferably, it is a film modified to have a surface tension of at least 40 dyne / cm and higher than the intrinsic surface tension of the polymer film by 5 dyne / cm or more.

As a surface modification method for improving surface tension,
Although not particularly limited, corona discharge treatment and glow discharge treatment are preferred. In particular, glow discharge treatment (also referred to as low-temperature plasma treatment) is performed in a vacuum deposition machine for depositing metal before or after forming a margin, or before or after depositing metal, using argon, air, oxygen, or the like. It can be easily formed by applying high voltage (DC, low frequency, medium frequency, high frequency, microwave, etc.) while flowing gas such as carbon dioxide, and effectively by exposing the polymer film to the glow discharge. This is a method that can modify the surface. Further, the method is excellent in quality without blocking phenomenon between the metal deposition layer and the surface-modified layer which is often observed in the case of corona discharge or the like.

Further, in the vapor deposition machine, after the metal is vapor-deposited, the metal-deposited layer and the margin portion are glow-discharged by using a gas such as argon, oxygen, air, nitrogen, water or a mixed gas thereof, particularly a gas containing oxygen atoms (low temperature). Exposure to plasma) can suppress the phenomenon that the residual oil in the margin part diffuses to the surface of the vapor-deposited metal layer and deteriorates the adhesion between the films, and can further enhance the adhesion between the films. More preferred.

In general, a film capacitor using a polymer film is a round capacitor in which a metal vapor-deposited film is wound around a core, a flat capacitor which is pressed after winding a metal vapor-deposited film, or a flat capacitor which is flattened. Although there are laminated capacitors and the like, the metal-deposited film according to the present invention is effective for improving the problem of the capacitor squeaking for any capacitor. It shows an excellent improvement effect especially on flat type capacitors or multilayer type capacitors where noise is apt to occur.Especially, the capacitor element is formed flat by the cold press method, in which the adhesion of the film is weak, and the instantaneous pressure is applied at low temperature with strong pressure. It shows a remarkable improvement effect on the flat type capacitor, and an excellent capacitor can be produced by using the present metallized film.

[Measurement and Evaluation Methods of Physical Properties] (1) Surface Tension The surface tension was measured according to the wetting test method for polyethylene and polypropylene films of JIS-K-6768-1971.

(2) Evaluation of pressability Two metal vapor-deposited films were stacked and wound, and a load was applied to both ends of the press-formed capacitor element using Tensilon (manufactured by Shimadzu Corporation) to open the core (forming). (Load collapsed) was read as press strength (kg). The greater the load, the better the pressability.

(3) Intensity of squeal of capacitor (volume of sound generated) After the element is wound, a metal element and a capacitor element provided with a lead terminal are connected to an LCR METER TY manufactured by Ando Electric Co., Ltd.
A voltage of 5 V was applied by PE AG-4311, and the portion where the generated sound volume was highest between the frequencies of 2 and 20 kHz was defined as the squeal intensity of the capacitor. Generated sound volume is RION Corporation
, A noise measuring instrument: using a type NA-29, separating the sound collecting microphone from the condenser element by 1 cm,
It is called dark noise. ) Was measured at a place of 52 to 53 dB.

[0021]

EXAMPLES Example 1 and Comparative Example 1 In Example 1, a 15-kHz polyethylene terephthalate film was supplied at a rate of 15 kHz while flowing 200 cc / min of oxygen and argon on a non-deposition surface in a vacuum deposition machine.
After applying a voltage of 1 kV and performing glow discharge treatment, oil was deposited on the surface opposite to the surface subjected to glow discharge treatment, and the width was 4 mm.
Was formed, and then Al was vapor-deposited to prepare a metal-deposited film for a capacitor in which the resistance value of the metal-deposited layer was 4Ω / □. The surface of the film subjected to the glow discharge treatment (the surface modified surface) has a surface tension of 42 dyn as compared with that before the treatment.
It increased from e / cm to 50 dyne / cm and 8 dyne / cm.

In Comparative Example 1, vapor deposition was performed in the same manner as in Example 1 except for the glow discharge treatment. Next, these metal vapor-deposited films were slit into a margin width of 2 mm and a film width of 20 mm, and then wound with an element to produce an element of about 0.3 μF.

Using these devices, at 120 ° C. and 30 k
After pressing under the conditions of g and 6 minutes, pressability was evaluated. Ten elements were measured, and the average value was defined as the press strength. After winding the element in the same manner as in the evaluation of pressability, the temperature was set to 120 ° C and 30 ° C.
The generated sound volume of the five elements subjected to metallikon and lead terminals after pressing for 6 minutes at kg was measured, and the average value was defined as the intensity of the squeal. Table 1 shows the results of these evaluations.

[0024]

[Table 1]

As is evident from Table 1, when the surface opposite to the metal-deposited surface was modified by glow discharge treatment, the pressability was improved and the noise of the capacitor was eliminated.

Examples 2 and 3 and Comparative Example 2 In Example 2, glow discharge treatment and an oil margin were formed on a 9 μm-thick polyethylene terephthalate film in the same manner as in Example 1, and then Al and Zn were deposited to form a margin width. A metal-deposited film for a capacitor having a thickness of 4 mm and a resistance value of the deposited metal layer of 6Ω / □ was prepared. In Example 3, after the metal deposition of Example 2 was performed, the metal deposition surface and the margin were subjected to glow discharge treatment in the vapor deposition machine under the same conditions as in Example 1. In Comparative Example 2, the glow discharge treatment was not performed.
Vapor deposition was performed under the same conditions as described above.

After slitting these metal-deposited films to a margin width of 2 mm and a film width of 24 mm, the element is wound,
An element having a size of about 0.25 μF was prepared, and the device of Example 1 and Comparative Example 1 were prepared.
The pressability and the squealing strength were evaluated in the same manner as described in the above section. Table 2 shows the evaluation results.

[0028]

[Table 2]

As is apparent from Table 2, the non-deposited surface subjected to glow discharge treatment has improved pressability and reduced capacitor squeal. In the case where the vapor deposition surface was glow-treated (Example 3), further effects were recognized in the pressability and the elimination of the squeal of the capacitor.

Examples 4 and 5, Comparative Example 3 A polypropylene film having a thickness of 8 μm was formed under ordinary conditions, and the surface on which metal was deposited was subjected to a known corona discharge treatment to a surface tension of 42 dyne / cm. The surface is 33 dyne / cm in Example 4, and 36 dyn in Example 5.
e / cm, and in Comparative Example 3, the non-deposited surface was not treated and the surface tension was 32 dyne / cm.

Using these films, an oil margin was formed on the surface on which metal was to be deposited, and a deposited film for capacitors having a resistance value of the deposited Al metal layer of 4 Ω / □ was prepared.

Using these metal-deposited films slit in a margin width of 2 mm and a film width of 25 mm, an element of about 0.5 μF was prepared. This device was heated at 95 ° C, 6
Example 1 after pressing under the condition of 0 kg / cm ² for 6 minutes
Pressability and squealing strength were evaluated by the methods described in the section of Comparative Example 1. Table 3 shows the evaluation results.

[0033]

[Table 3]

As is clear from Table 3, the one in which the surface tension is increased by the surface modification of the non-evaporated surface has improved pressability and improved squeal of the capacitor.

[0035]

According to the present invention, a discharge treatment is performed on at least the non-deposited surface side of the base material to raise the surface tension by 1 dyne / cm or more higher than the surface tension of the base film, whereby the deposited film is formed. The pressability of the used capacitor can be improved, and the squeal of the capacitor can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a metal-deposited film for a capacitor according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 metal-deposited film 2 polymer film 3 metal-deposited layer 4 margin part 5 margin oil 6 non-deposited surface subjected to discharge treatment

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kenji Hatada 1-1-1 Sonoyama, Otsu-shi, Shiga F-term in the Shiga Works of Toray Industries (reference) 4F073 AA01 BA08 BA24 BB01 CA01 CA21 HA14 4F100 AB01B AB10 AK01A AK42 AK80B BA02 BA42 EH66B EJ52B GB41 JA20B JL00 4K029 AA11 AA25 BA03 BD00 CA01 DB03 FA05 GA02 GA03 5E082 AB03 AB05 BC40 EE07 EE24 EE25 EE38 EE45 FG06 FG34 FG35 FG36 FG56 HH10 MM22 MM23 PP23

Claims (8)

[Claims] 1. One side of a substrate made of a polymer film,
In a metal-deposited film having a metal-deposited layer serving as an electrode and a margin formed by oil, the surface tension of a surface opposite to the metal-deposited layer of the polymer film and the surface having the margin is 33 dyne / cm or more, and A metal-deposited film for a capacitor, wherein the film has a surface tension higher than that of a polymer film by 1 dyne / cm or more. 2. The surface tension of a surface opposite to a surface having a margin portion and a metal deposition layer of a polymer film is 40 dyne / cm.
5 dy from the surface tension inherent to the polymer film
The metal-deposited film for a capacitor according to claim 1, wherein the thickness is higher than ne / cm. 3. One side of a substrate made of a polymer film,
In producing a metal deposition film having a margin portion formed by oil and a metal deposition layer to be an electrode, in a vacuum deposition machine, before or after metal deposition, or before or after the margin portion formation, a metal deposition layer of a polymer film And subjecting the surface opposite to the surface having the margin portion to a discharge treatment. 4. The method for producing a metal-deposited film for a capacitor according to claim 3, wherein the metal-deposited layer and the surface of the margin portion are subjected to a discharge treatment after the metal is deposited in a vacuum deposition machine. 5. The method according to claim 3, wherein the discharge treatment is a glow discharge treatment. 6. A capacitor using the metal-deposited film for a capacitor according to claim 1. 7. The capacitor according to claim 6, wherein the capacitor is a flat capacitor or a multilayer capacitor. 8. The capacitor according to claim 7, wherein the flat type capacitor is formed by a cold press method.