JP2000164453A - Metal evaporated film and capacitor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal evaporated film for capacitor which can be pressed with high workability and can eliminate the resonance noise of a capacitor, by appropriately combining the average molecular weight of the oil forming the margin of the film with the average surface roughness of the film and a capacitor using the film. SOLUTION: In a metal evaporated film 1 having a metal evaporated layer 4 which becomes an electrode and a margin section 3 formed of oil 6 on one surface of a substrate composed of a high polymer film 2, the average molecular weight Mw of the oil 6 and the average surface roughness Ra (nm) of each surface of the film 2 are adjusted so that the ratio Mw/Ra of the average molecular weight of the oil 6 to the average surface roughness of the surface of the film 2 having the larger average surface roughness may meet a relation, 25<=Mw/Ra<=150.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-deposited film for a capacitor 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 onset voltage.On the other hand, this oil deteriorates the pressability of the element at the time of making the capacitor element. There is a problem that when a voltage is applied to the capacitor, the film vibrates and resonates and emits sound, a phenomenon called so-called squealing.

As a method for preventing the squeal phenomenon, US Pat.
Japanese Patent Publication No. 563,763 discloses a method of tightening a capacitor itself, and Japanese Patent Publication No. Hei 3-1247 discloses a method of bonding a film coated with a material having good adhesiveness to a metal-deposited film in order to increase the adhesion of the film. Has been proposed. However, these methods have problems that the materials and processing steps are increased, the manufacturing cost is increased, and the size of the capacitor is increased.

[0004] Japanese Patent Publication No. Hei 8-26449 discloses that
Weight-average molecular weight Mw as oil for margin formation
It has been proposed to use a perfluoroalkyl polyether (fluorine oil) having a molecular weight in the range of 1,000 to 15,000, but the use of a fluorine oil of a specific molecular weight can prevent metal adhesion in a margin portion. However, this method has a problem in that oil generally penetrates into the metal deposition layer, and the pressability deteriorates.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal-deposited film which improves the adhesiveness between films, has good pressability, and has little squeal, and a capacitor using the same.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a metal vapor deposition layer having an electrode on one side of a polymer film base and a margin formed by oil. The film was completed as a result of intensive studies not only on the weight average molecular weight Mw of the oil but also on the average surface roughness of the base film. That is, the metal-deposited film according to the present invention has a weight-average molecular weight Mw of oil in a metal-deposited layer having a metal-deposited layer serving as an electrode on one side of a substrate made of a polymer film and a margin portion formed of oil.
The ratio Mw / Ra of the average surface roughness Ra (nm) of the larger one of the average surface roughnesses of the respective surfaces of the base film to 2 is 2
It is characterized by satisfying 5 ≦ Mw / Ra ≦ 150.

Further, the capacitor according to the present invention is constituted by using such a metal-deposited film. The capacitor can be formed into, for example, a flat type or a multilayer type capacitor.

[0008]

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

FIG. 1 shows a schematic configuration of a metal-deposited film 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 the entire metal-deposited film according to the present invention, 2 denotes a base made of a polymer film, and 3 denotes whether or not a metal-deposited layer is formed or metal oxide or the like. An insulating portion (hereinafter, referred to as a margin) for maintaining insulation from a counter electrode when the capacitor is formed by the formed insulating portion, 4 is a metal deposition layer, 5 is a boundary film portion between the metal deposition layer and the margin portion, 6 Is an oil for forming a margin.

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. 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 applied on a polymer film by vapor deposition or transfer to prevent adhesion of the vapor-deposited metal. Refers to an insulating part provided to insulate the device. 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 when forming a flat type capacitor (press type capacitor), The pressability of the film is deteriorated, and the adhesion between the films is poor, so that when the AC voltage is applied to the capacitor, the film vibrates and emits a sound, that is, a so-called squealing phenomenon is easily generated. 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 pressability and squealing phenomena.
w and the average surface roughness Ra (nm) of the average surface roughness of each surface (that is, both surfaces) of the substrate film
The ratio Mw / Ra to a must satisfy 25 ≦ Mw / Ra ≦ 150.

That is, when the vapor deposition surface is a rough surface, the Ra of the surface is specified, and when the non-deposition surface is a rough surface, the Ra of the surface is specified. The reason for defining the Ra on the rough side of the base film in this way is that when the base films (metal-deposited films) are overlapped, the rule of the property improvement is the rough side. .

If Mw / Ra is less than 25, the applied oil penetrates through the voids of the vapor-deposited film to the metal-deposited portion, hinders the close contact between the films, and worsens the pressability and hence the squeal phenomenon. Preferably, 35 ≦ Mw /
Ra ≦ 70. If it is in the range of 35 ≦ Mw ≦ 70 and Mw is 5,000 or less, ease of oil application,
And uniform application is possible, which is more preferable.

On the other hand, if Mw / Ra exceeds 150, high viscosity and low vapor pressure result, so that the heating temperature of the margin oil nozzle becomes high during oil application, causing a drawback that uniform application is difficult.

For these reasons, Mw is 800-
It is preferably in the range of 5,000,
A range of 4,200 is more preferred.

The oil used in the present invention is not particularly limited.
The molecular weight distribution of the oil is narrow and sharp due to the ease of oil application, etc. It has a moderate vapor pressure that is not too high or too low because it is applied to the substrate in a vacuum evaporation machine, and the margin Those having a surface tension and an appropriate viscosity that can be stably applied to the portion without unevenness are preferable.

Examples of oils satisfying these requirements include silicone oil and fluorine oil.
Fluorine oil is particularly preferred from the viewpoints of molecular weight, vapor pressure and sharpness of molecular weight distribution.

There is a margin formed by an oil satisfying the above requirements, and a width between the metal deposition portion and the margin portion where the metal deposition film thickness is continuously reduced from the metal deposition portion to the margin portion. A capacitor using a metal-deposited film having a boundary film portion of 1 to 1 mm has good adhesion, mitigates the squealing phenomenon, and has a high withstand voltage. Especially suitable for

[Measurement and Evaluation Methods of Physical Properties] (1) Weight average molecular weight (Mw) of margin oil Gel permeation chromatography GPC-224 (WATER)
S), detector: differential refractive index detector R-401 (WATE)
RS), and molecular weight calibration was performed with polystyrene. In the case of a silicone oil having a phenyl group, TSK-gel-G3000HXL (1), G25
00HXL (1) (manufactured by Tosoh Corporation) was used.

(2) Average surface roughness (R) of the base film
a) It was measured according to JIS-B0601-1976. However, the cutoff was 0.25 mm.

(3) 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. Collapsed)
The load at this time was defined as press strength (kg). The higher the press strength, the better the pressability.

(4) Crying strength of the condenser (volume of generation) A voltage of 205 V was applied using a withstand voltage pulse tester MODEL: TP-500 (manufactured by Busan Sokki Co., Ltd.), and RION Corporation was used.
Using a precision sound level meter: NA-29E, the sound collecting microphone was separated from the condenser element by 5 cm, and the room noise (background noise) was measured at a place of 38 to 39 db.

(5) Boundary film width The interface between the deposited film and the margin is made of PROFIL manufactured by Nikon.
Using EPROJECTOR V-12, the sample was observed at a magnification of 50 times, and the DIGITALCOUN manufactured by Nikon was used.
Read with TER CM-6S.

[0027]

EXAMPLES Examples 1 and 2 and Comparative Examples 1 and 2 In Example 1, a polyethylene terephthalate film having a thickness of 11 μm and a surface having a large average surface roughness (hereinafter abbreviated as Ra) having a mean surface roughness Ra of 34 nm was used. In a vacuum evaporator, a purple olopolyether having an oil weight average molecular weight Mw of 1,720 (Fomblin Y04, manufactured by Audimont Co., Ltd.) was used as a margin oil, and the product width was 24 m.
m, Al is 6 (Ω / □) so that the margin width is 2 mm
Was deposited with a film resistance of. Here, Mw / Ra was 51.

In Example 2, the oil had a Mw of 4,240
Perfluoropolyether (Audimont Co., Ltd.)
Fomblin Y45) was used, and the others were deposited in the same manner as in Example 1. Here, Mw / Ra was 125.

In Comparative Example 1, a silicone oil having an Mw of 514 and methylphenyldimethylpolysiloxane (SH-702, manufactured by Dow Corning Toray Co., Ltd.) were used as the oil, and the other conditions were the same as in Example 1. Mw of this condition
/ Ra was 15.

In Comparative Example 2, the oil had an Mw of 6,250.
And the other conditions were the same as in Example 1. Mw / Ra here was 184. In Comparative Example 2, even when the temperature of the margin nozzle was increased to 200 ° C., sufficient oil application was not possible due to the low vapor pressure of the oil, and a necessary margin could not be formed.

After slitting these vapor-deposited products, the device was wound to form a capacitor device of about 1 μF. Using this device, pressability was evaluated after pressing under the conditions of 120 ° C., 60 kg / cm ² , and 6 minutes. Ten elements were measured under each condition, and the average value was defined as the press strength. After the element was wound and pressed in the same manner as in the evaluation of pressability, metallicon and lead terminals were attached, and then a drying process was performed.
Under the conditions of Hg-abs or less, dimethylpolysiloxane (manufactured by Dow Corning Toray, SH-200, 100c
st) was impregnated for 24 hours, and after cooling, exterior covering was performed with a polyurethane resin.
The average value was defined as the intensity of the squeal = the generated volume. Table 1 shows the results of these evaluations.

As is apparent from Table 1, Mw / Ra is 2
Examples 1 and 2 in the range of 5 to 150 have high press strength and reduced squeal.

[0033]

[Table 1] Examples 3 to 6 and Comparative Examples 3 to 5 In Example 3, a polypropylene film having a thickness of 8 μm and a Ra film of 58 nm was replaced with a perfluoropolyether having an Mw of 2,180 (Fombrin Y0 manufactured by Audimont Co., Ltd.).
Using 6) as a margin oil, Al was deposited with a film resistance of 6 (Ω / □) so as to have a product width of 25 mm and a margin width of 2 mm.

Similarly, in Examples 4, 5, and 6, and Comparative Examples 3 and 5, the Ra of the polypropylene film and the Mw of the oil were changed.
4 and 5 were deposited. The Mw of the oil used and the Ra of the film are as shown in Table 2.

After slitting these vapor-deposited films and winding the element so that the capacitance becomes about 1 μF, at 105 ° C. and 60 kg
After pressing under the conditions of 6 cm / cm ² and 6 minutes, the pressability of 10 elements was evaluated under each condition.

In the same manner, after the element was wound and pressed, metallicon terminals were attached, and after covering with a polyurethane resin, the generated sound volume was measured. Table 2 shows these test conditions and evaluation results.
It was shown to.

As is clear from Table 2, those having Mw / Ra of less than 25 have poor pressability and high squealing level.
When Mw / Ra is in the range of 25 ≦ Mw / Ra ≦ 150, both the pressability and the squeal are improved.

[0038]

[Table 2]

Example 7 and Comparative Example 6 In Example 7, vapor deposition was carried out in the same manner as in Example 4, the margin oil amount was controlled, and a 0.28 mm boundary film portion was formed between the metal deposition portion and the margin portion. Was generated.

In Comparative Example 6, the specifications such as the product width were the same as in Example 7, and the margin was formed by a tape margin. In Comparative Example 6, the width of the boundary film portion was as small as almost zero.

Using these vapor-deposited products, devices were prepared in the same manner as in Example 4, and after packaging, 10 devices were used for each condition under AC-15.
After applying a voltage of 00V for 1 minute, the capacity decrease was measured,
The average value was defined as the capacity reduction rate. The results are shown in Table 3.

[0042]

[Table 3]

As is clear from Table 3, the metal-deposited film having the boundary film portion of 0.1 to 1 mm has a high AC withstand voltage, so that it does not break even in a severe withstand voltage test and has a reduced capacity. It turns out that it has few excellent characteristics.

[0044]

As described above, according to the present invention,
By appropriately combining Mw of the margin oil and Ra of the film and designing the range of 25 ≦ Mw / Ra ≦ 150, it is possible to provide a capacitor with good pressability and improved squealing phenomenon.

Further, by providing a boundary film portion having a width of 0.1 to 1 mm, a highly reliable capacitor having an extremely high AC withstand voltage can be provided.

[0046]

[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]

 DESCRIPTION OF SYMBOLS 1 Metal vapor deposition film 2 Polymer film 3 Margin part 4 Metal vapor deposition layer 5 Boundary film part (width: L) 6 Margin oil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 4/24 331Z F-term (Reference) 4F100 AB01B AB10 AK01A AK17B AK42 BA02 BA41 DC21B DD07 DD07A EH66B GB41 JA07 JA07B JL00 JL11 YY00 4K029 AA11 AA25 BD00 5E082 AB03 AB05 BB10 BC31 BC40 EE07 EE23 EE38 FG06 FG34 FG48 PP04 PP10

Claims (9)

[Claims] 1. A metal-deposited layer serving as an electrode on one side of a base made of a polymer film, and a metal-deposited film having a margin formed by oil. A metal-deposited film, wherein the ratio Mw / Ra to the average surface roughness Ra (nm) of the larger one of the average surface roughness of the surfaces satisfies 25 ≦ Mw / Ra ≦ 150. 2. The metal-deposited film according to claim 1, wherein 35 ≦ Mw / Ra ≦ 70 is satisfied. 3. The metal-deposited film according to claim 1, wherein the oil is a fluorine oil. 4. The oil has a weight average molecular weight Mw of 800 or more.
4. The method according to claim 1, wherein the distance is in the range of 5,000.
5. The metallized film according to any one of the above. 5. The oil having a weight average molecular weight of 1,500 to 500.
The metallized film according to claim 4, which is in the range of 4,200. 6. A boundary film portion having a width of 0.1 to 1 mm between the metal deposition portion and the margin portion, wherein the metal deposition film thickness is continuously reduced from the metal deposition portion to the margin portion. 6. The metallized film according to any one of 1 to 5. 7. A capacitor using the metal-deposited film according to claim 1. 8. The capacitor according to claim 7, wherein the capacitor is a flat type or a multilayer type capacitor. 9. The capacitor according to claim 7, wherein the capacitor is a safety standard capacitor.