JPH0457310A - Manufacture of metallized film capacitor - Google Patents

Abstract

PURPOSE:To manufacture a capacitor excellent in characteristics, with high efficiency, by winding a metallized film while exfoliating it from the metallized film provided with the retaing body film on a winding shaft, and obtaining a metalized film winding body. CONSTITUTION:A metalized film obtained by exfoliating a retaining body film 9 from a metallized film 4 provided with the retaining body film wherein a plastic film surface is metallized is wound around a winding shaft 2, and a metallized film winding body turning to the capacitance generation part of a capacitor is obtained. In the manufacturing process of this winding type or laminated layer type metallized film capacitor, while the retaining body film 9 is exfoliated from the metallized film 4 provided with the retaining body film, the metallized film is wound around the winding shaft 2, thereby obtaining the metallized film winding body. Hence, when a capacitor is manufactured by using a very thin metallized film, the generation of imperfect breakdown strength is restrained to a minimum, and a very small-sized capacitor for the electrostatic capacity can be manufactured with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing metallized film capacitors.

[Prior Art] It is known to obtain a metallized film capacitor by winding or laminating metallized films.

Moreover, as an effective means to obtain an ultra-thin metallized film, a metallized film is obtained by peeling the support film from a metallized film with a support film in which the metallized film is removably laminated on the support film. Is it possible to obtain a capacitor by winding and laminating metallized films?
It is known from Publication No.-163419 and the like.

[Problems to be solved by the invention] However, capacitors obtained by winding and laminating metallized films obtained by peeling the support film from a metallized film with a support film have poor withstand voltage and insulation resistance. There was a problem that defects occurred frequently. This is because the metallized film obtained from the metallized film with a support film is usually an extremely thin film, so in the process where the metallized film alone is handled, there is a problem between the metal holes that come into contact with the film or between the films. Possible reasons include that insulation defects (pinholes) are likely to occur due to the slightest amount of friction, or that the lack of slipperiness after peeling may cause misalignment or wrinkles during winding.

The present invention solves the above problems and makes it possible to efficiently manufacture a capacitor with good characteristics from a metallized film and a metallized film with a support film which are laminated in a peelable manner. The purpose is to provide a method.

[Means for Solving the Problems] In order to solve the above problems, the present invention has the following configuration. That is, in a plastic film with a support film in which a plastic film is releasably laminated on at least one side of the support film, the support film is peeled from the metallized film with a support film obtained by metallizing the plastic film surface. The obtained metallized film is wound around a winding shaft to obtain a metallized film roll that becomes the capacitance generating part of the capacitor, and then the winding is performed in a method for manufacturing a wound type or laminated type metallized film capacitor. This method of manufacturing a metallized film capacitor is characterized in that the metallized film capacitor is rolled while peeling the support film from the metallized film with the support film on a rotating shaft -F to obtain a metalized film wound body.

In the present invention, a plastic film (hereinafter sometimes referred to as a dielectric film) refers to a thin film made of a polymer resin composition, and includes polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, bodether ether, etc. A biaxially stretched film obtained by melt-extruding, biaxially stretching, and heat-setting a resin composition containing a crystalline thermoplastic resin such as ketone as a main component is preferable from the viewpoint of the characteristics of the resulting capacitor. The present invention is most effective when the thickness of the film is 0.2 μm or more and 1°0 μm or less.

The present invention uses a plastic film with a support film (hereinafter sometimes referred to as a laminated film) that is releasably laminated on at least one side of the plastic film or the support film. Here, peelable means that the peeling force between the dielectric film and the support film is 10 g/c.
m or less. If the peeling force is 3.0 g/cm or less, the dielectric film will not be substantially damaged, and if it is 0.3 g/cm or more, it will not peel off when processing with a support film. This is preferable in that it prevents troubles that may occur. Further, the thickness of the support film is preferably 2 times or more and 10 times or less than the thickness of the dielectric film from the viewpoint of handling properties in a laminated film state.

It is preferable that the surface roughness (Ra) of the side of the laminated film on which the dielectric film is provided is 0.005 to 0.15 μm from the viewpoint of the handling properties of the film and the characteristics of the capacitor. Also, the coefficient of friction of the laminated film is 0.0 when the dielectric film side surface and its back surface are overlapped. 4
~1.5, and a dynamic friction coefficient of 0.3 to 0.8 is preferred from the viewpoint of suitability for processing such as slitting and vapor deposition, and windability of capacitor elements.

The material of the support film may be selected depending on the material of the dielectric film, the method of lamination, etc., or the laminated film used in the present invention may be obtained by co-extrusion or co-stretching. A film of a crystalline thermoplastic resin composition is preferred also as the support film from the viewpoint of ease of handling. As a preferred combination of the dielectric film material and the support film material, when the dielectric film material is polyester such as polyethylene terephthalate or polyethylene naphthalate, the support film material is preferably polyolefin or boarylene sulfide. Ethylene component as polyolefin
Ethylene copolymerized polypropylene copolymerized with ~6 mol% is preferred.

As the polyarylene sulfide, polyphenylene sulfide is preferred. Among these, polyphenylene sulfide is most preferred from the viewpoint of ease of handling the laminated film. Further, when the dielectric film material is polyphenylene sulfide, the support film material is preferably a polyester having a melting temperature of 260° C. or higher, such as polyethylene terephthalate or polyethylene naphthalate.

Among these, polyethylene terephthalate is preferred from the viewpoint of handling properties of the laminated film and co-stretchability with polyphenylene sulfide.

In the present invention, first, the dielectric film surface of the laminated film is metallized. Here, metallization refers to forming a metal thin film on a film by methods such as vapor deposition, sputtering, and plating.

Among these methods, the method using vapor deposition is preferable from the viewpoint of productivity and characteristics of the obtained capacitor. As the metal species, aluminum, zinc, nickel, copper, etc. are used, and among these, aluminum is preferable from the viewpoint of the characteristics of the capacitor obtained. However, a small amount of other metals such as nickel, copper, gold, and silver may be included for the purpose of improving the adhesion of the deposited film or the like. From the viewpoint of moisture resistance and voltage resistance of the capacitor, the preferred thickness of the deposited film is 0.000000000000000000000000000000000,000 The resistance is 5Ω or more and 10Ω or less, more preferably 2.0Ω or more and 5.0Ω or less.

The metallized film with a support film (hereinafter also referred to as metallized laminated film) obtained in this way has a non-metalized band called a margin running in the longitudinal direction of the film before or during winding. provided. Margins can be formed by masking the desired position of the film with tape or oil during the metallization process, or by metallizing the entire surface of the film and then removing the deposited film using a laser beam, electrical discharge, etc. A method of providing a margin can be adopted. Among these, the method using a laser beam is preferable in terms of margin accuracy.

The metallized laminate film can then be slit into a tape with the undeposited portion running to the left or right. At this time,
The film can be slit so that the left or right end becomes the non-deposited part, or it can be of a so-called inner margin type, in which the non-deposited part runs slightly inside the left or right end of the film. Alternatively, at this stage, it is also possible to obtain a wide rolled body having a plurality of capacitance generating portions in the width direction without slitting it into narrow widths, and then divide it in the width direction.

Next, a metallized film roll that will become the capacitance generating portion of the capacitor is manufactured using a device capable of simultaneously peeling off the metallized laminated film and winding the element. Here, the capacitance generating portion refers to a portion in which dielectric films and metal thin films serving as internal electrodes are alternately laminated.

When the metallized laminate film is slit to a narrow width (one film corresponds to one margin), two tape-shaped metallized laminate films with margins on the left and right are each slit into non-slit widths (one film corresponds to one margin). Wind it so that the margin ends are slightly offset and overlapped. When obtaining a wound type capacitor, the winding shaft is a small cylinder with a diameter of several millimeters, and when obtaining a laminated capacitor, a wheel-shaped winding shaft with a diameter of several tens of centimeters is used. Generally, it is wound around a flat plate-shaped winding shaft.

It is also possible to preform during winding using a heated press roll or the like. In this case, it is also preferable to improve the adhesion between the metallized films by a method such as discharge treatment, coating, or formation of an easy-to-adhesion layer on the metallized and/or non-metallized surfaces of the metallized films.

You can also wind a wide film (one film corresponds to two or more margins), or slit a wide film just before winding and wind multiple tape-shaped metallized films in the width direction. Even when a method of obtaining a plurality of elements across the width of the film by winding it around an axis is adopted, a method of stacking two or more single-sided metallized films can be adopted. Furthermore, there is also a method of winding a sheet of single-sided metallized film in which the margin position is alternately shifted for each turn of winding. The shape of the winding shaft may be cylindrical, wheel-like, flat plate-like, etc. as described above. These methods are particularly effective in obtaining multilayer capacitors. In these methods, in view of the problem of margin position accuracy during winding, a method is preferably used in which a metallized laminated film is vapor-deposited over the entire surface of the film and a margin is provided by a laser beam or the like before or during winding. Furthermore, an inner margin type margin is preferably used to prevent adjacent capacitor elements from having an adverse effect on each other.

The key point of the present invention is to peel the support film from the metallized laminated film on the winding shaft when obtaining the metallized film roll as shown above. It is.

Here, peeling "on the winding axis" means that the point at which the support film is peeled from the metallized laminate film is on the axis around which the metallized film is wound (corresponding to the winding axis in the above example) or This means that it is on the metallized film roll that is in the process of being rolled. Since the present invention has such a configuration, it is not possible to adopt a method of overlapping two metalized films and then winding them.
A method is adopted in which the sheets are wound around the winding shaft one by one.

The support film is peeled off from the side opposite to the metallized dielectric film side of the metallized laminate film by passing a freely rotatable peeling roll through the support film onto the metallized film roll that is in the middle of being wound. It is preferable to bring them into contact and peel off the support film by making only the support film run along the peeling roll.

At this time, it is also preferable to press the peeling roll against the wound body with a pressure within a range that does not substantially damage the dielectric film.

The metallized film roll thus obtained is subjected to post-processing depending on the needs of the desired capacitor. Post-processes include the following steps.

First, the metallized film roll is heated and/or pressurized and shaped before or after being removed from the winding shaft to obtain a capacitor element or a capacitor mother element. A flat winding shaft is advantageous in that parallel flat plate pressing can be performed with high accuracy without removing the metallized film roll from the winding shaft. In addition, if a method is used in which preforming is performed during winding using a heated press roll, the film will not come apart even if the metallized film roll is removed from the winding shaft, so parallel plate pressing is still possible. be. In the case of a metallized film roll that has multiple capacitance-generating parts in the width direction, it is formed by heating and/or pressurizing before or after being removed from the winding shaft, and then divided by cutting it in the width direction. Obtain a capacitor element or a capacitor mother element. In addition, when dividing in the width direction by cutting after winding, the cut surface where the external electrode is to be provided is relatively smooth, and the electrical and mechanical connection between the external electrode and the internal electrode (metal thin film) is ensured. Therefore, it is preferable to take measures to strengthen the contact between the external electrode and the internal electrode using a physical or chemical method on the cut surface before winding or after cutting.

Such techniques include creating defects (holes, dents, etc.) in the film before winding along the planned cutting line so that the cut surface becomes uneven, and There are methods to create irregularities using methods such as plasma etching and sandblasting, and methods to chemically improve adhesion using electrical discharge treatment. The obtained capacitor element or capacitor mother element is provided with external electrodes that are electrically connected to the metal thin film on the film that will serve as internal electrodes, by a method such as metal spraying or coating with a conductive resin. The capacitor mother element is then cut into individual elements so as to have optimum capacitance to form capacitor elements. After that, depending on the needs of the desired capacitor, there is a heat treatment process, an impregnation process with resin, wax, etc. under vacuum or long-term immersion, and lead wire attachment is done by a process such as resin molding, resin coating, film, sheet pasting, etc. Capacitors are obtained through the packaging process.

Further, in the case of a dielectric film or a polyphenylene sulfide film, the dielectric film has high heat resistance, so that it can be used as a so-called chip capacitor without lead wires. In this case, it is preferable to make the exterior as simple as possible from the viewpoint of downsizing the capacitor.
It is preferable to apply a highly heat-resistant resin such as polyimide or epoxy to the cut surface of the element, or to attach a highly heat-resistant film such as a polyimide film. In addition, the characteristics of the capacitor will be stabilized if heat treatment is performed at a temperature of 200°C or more and 265°C or less for 1 hour or more at any stage after the film is wound until it becomes a capacitor, preferably after the external electrodes are provided. preferable.

[Effects of the Invention] According to the method for manufacturing a metallized film capacitor of the present invention, the occurrence of withstand voltage defects is minimized, especially when manufacturing a metallized film capacitor using an ultra-thin metallized film. Ultra-small capacitors can be manufactured extremely efficiently for that capacitance.

[Characteristics evaluation method] The evaluation method of each characteristic in the present invention will be explained below.

(1) Surface roughness Measured according to JIS R-0601.

(2) Peeling force When the width of the laminated film is W (cm), the surface film layer is continuously peeled at 200mm/m at a peeling angle of 180 degrees.
The tension applied to the surface film when it is peeled off at a speed of 1.5 in is measured using a tensiometer. When the tension at this time is T (g), peeling force (g/cm) = T/W was calculated.

(3) Surface resistance of metallized film Place the metallized film to be measured on a thick rubber sheet with the metallized side facing up, and place two squares facing each other on top of it.
It has the length of one side of the square so as to form a side, and 1 of the length
, / ], 2 with a smooth polished bottom with a width of 0
Two rectangular brass electrodes were placed, and the electrical resistance between the two electrodes was measured while applying a pressure of 0.2 kg/cm 2 from above the electrodes. At this time, the size of the electrode is appropriately selected depending on the size of the deposited film to be measured.

(4) Capacitor withstand voltage failure rate Measure the DC withstand voltage of the capacitor. The applied voltage increase rate was 100V/sec, and the rate was 50V/sec depending on the film thickness.
A capacitor element that was destroyed by a voltage of V/μm or less was determined to be a defective element with withstand voltage, and the defective rate (%) was calculated.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples.

Example 1 (1) Production of metallized laminated film Q containing 5 wt% of spherical silica with a diameter of 500 mμ, 30
Polyphenylene sulfide with a melt viscosity of 4000 poise under a shear rate of 200 5 ec-' at 0°C9, and an intrinsic viscosity of 0. The polyethylene terephthalate in Step 7 is supplied to separate extruders, guided in a molten state by a double-tube lamination device located at the top of the nozzle so that the center layer becomes polyethylene terephthalate, and then discharged from the T-die type nozzle provided. The mixture was rapidly cooled in a cooling rotating drum to obtain a substantially amorphous three-layer laminate sheet of polyphenylene sulfide/polyethylene terephthalate/polyphenylene sulfide.

Next, the laminated sheet was made to run in contact with a plurality of heating rolls having a surface temperature of 90°C, and was rolled 3 times in the longitudinal direction between the heating roll group and a cooling roll having a different peripheral speed of 30°C, which was provided next to the heating roll group.
It was stretched 7 times. This uniaxially stretched sheet was stretched 3.5 times in the direction perpendicular to the longitudinal direction at 100°C using a tenter, and then heat treated at 245°C for 10 seconds to form a polyphenylene sulfide film with a thickness of 0.7 μm or a polyphenylene sulfide film with a thickness of 2 A laminated film was obtained by laminating both sides of a .5 μm polyethylene terephthalate film. The peeling force of this laminated film is 1.8
g/cm. Moreover, the surface roughness Ra was 0.03 μm.

The laminated film thus obtained was applied to a continuous winding type vacuum deposition machine, and aluminum was deposited on one side to a thickness of 350 angstroms. The surface resistance value of this metallized laminate film was 3.5Ω.

(2) Manufacture of capacitors The metallized laminated film obtained in (1) above is slit to a width of 50 mm, and eight non-metalized bands (margins) are formed on the metalized surface of the metalized laminated film that is run using a YAG laser. A metallized laminated film reel with a margin was obtained. At this time, the average margin width was 0.15 mm, and the pitch (margining interval) was 4.0 mm on average. In addition, in consideration of film breakage caused by damage to the film caused by the laser, a non-margin portion (edge) of 10 mm or more was left on both sides.

Next, two of the metalized laminated film reels with margins were used as a set to obtain a metalized film roll having eight capacitance generating portions in the width direction using the apparatus shown in FIG. The apparatus shown in Fig. 1 has a winding shaft (drum) 2 with a diameter of 600 mm and two film unwinding devices at opposing positions of the winding shaft, and furthermore, one tape-shaped metallized laminated film is rolled out per margin. The slitting blade 5 and receiver provided to obtain a slitting device include a slitting device having a blade roll 6, a touch roll for winding around the winding shaft, a peeling roll 8 for peeling off the support film, and a metallized dielectric film for winding. A heating press roll 7 is heated and pressed onto the metallized film roll 1 during rotation,
This element winding machine is provided with two elements corresponding to two film unwinding devices, and is capable of performing each of these steps in succession in this order. At this time, the metallized laminated film 4 was set so that the surface on which the metallized film was provided was wound inside the metalized film roll. The slit position is near each margin (one reel is on the right side of the margin, the pond reel is on the left side of the margin) 0
．． The position was set at 2 mm.

Further, the reel position and the slit position were adjusted so that the slit tape-shaped metallized laminated films were alternately overlapped with each other while protruding 0.2 mm from the non-margin end.

Moreover, the surface temperature of the heating press roll was 2500C.

The number of rotations (turns) for winding on the winding shaft was 1000 turns. The metallized film roll obtained in this way was cut at one point on the circumference, and further divided along the slit positions in a peeling motion to form 8 pieces of laminated 2000 layers of metallized film. A capacitive generator (rope) was obtained.

Next, cut the rope into 30cm lengths, and cut the rope into 4mm widths above and below.
By stacking 250μm thick polyphenylene sulfide films (Torelina manufactured by Toshi Co., Ltd.) cut into 2mm and 30cm lengths, sandwiching them between square iron bars from above and below, and tightening the two square iron bars with bolts. While applying an average pressure of 20 kg/cm2 or more, a metal mainly composed of aluminum and then a metal mainly composed of copper are sequentially melted and sprayed onto the end face of the capacity generating part where the metallized film is laminated. An external electrode was provided.

Next, in this state, the temperature is increased to 2 in a hot air oven.
Heat treatment was performed at 50° C. for 10 hours, and the bolts on the square iron bar were loosened to obtain a capacitor mother element provided with external electrodes.

The obtained capacitor mother element was cut into lengths of 4.5 mm to obtain capacitor elements, and the external electrode portions were solder-plated to obtain a chip capacitor.

After manufacturing 1000 capacitors using this method,
Average capacitance is 0.55μF, capacitance variation (capacitance standard deviation of individual capacitor divided by average capacitance, %
) was 6%. Also 25℃, 1kHz
The dielectric voltage junction (fan δ) at z was 0.06% on average, and its variation (calculated in the same manner as above) was 28%. The withstand voltage failure rate is as low as 4%, ensuring sufficient practicality and productivity (
yield).

Comparative Example 1 The peeling roll 8 of the device shown in FIG. 1 used in Example 1 was removed, and the peeling roll was replaced in a position immediately after the unwinding device, so that the peeling occurred between the unwinding device and the slitting device. Example 1 Capacitor production was attempted in the same manner as in Table 1. However, when margining the film after peeling, wrinkles appeared intermittently due to damage to the dielectric film caused by the laser, and the number of turns on the winding shaft during slitting was 5.
The film ran out or sputtered between 0 and 300 turns, and could not be wound stably over 1000 turns.

Also, if the number of turns is insufficient due to the film running out, stack some ropes and make 1000 metalized films.
A chip capacitor was manufactured in the same manner as in Example 1 after the layers were laminated, but the capacitance variation was 24%, the dielectric loss tangent variation was 57%, and the withstand voltage failure rate was 43%.
Productivity was poor, and only inferior quality capacitors were obtained.

[Brief explanation of the drawing]

FIG. 1 shows an example of an apparatus for carrying out the method of manufacturing a metallized film capacitor of the present invention.
1 is a schematic diagram of an element winding machine used in Metalized film roll 2 in the middle of winding: Winding shaft 3: Unwinding shaft 4: Metallized laminated film 5 Nislit blade 6: Receiving blade roll 7: Heat pressing roll 8: Peeling roll 9: Support film 10 :Support film winding shaft patent applicant Toshi Co., Ltd. Figure 1

Claims (1)

[Claims] (1) Peeling the support film from the metallized film with the support film obtained by metallizing the plastic film surface of the plastic film with the support film, in which the plastic film is releasably laminated on at least one side of the support film. In the method of manufacturing a wound type or laminated type metallized film capacitor, the metallized film obtained by the above method is wound around a winding shaft to obtain a metalized film wound body which becomes a capacitance generating part of the capacitor. A method for manufacturing a metallized film capacitor, which comprises winding the metallized film with a support film while peeling the support film on a winding shaft to obtain a metallized film wound body.