JPH0810661B2 - Film capacitor material tape coil and method of manufacturing the same - Google Patents

Description

The present invention relates to a tape coil used as a material for a film capacitor and a method for manufacturing the same.

[Conventional technology and its problems]

Among non-electrolytic capacitors, film capacitors
There are a synthetic resin film as a dielectric and a tape on which a metal as an electrode is vacuum-deposited, and a film and a metal foil alternately laminated and wound.

The latter is usually manufactured by alternately laminating two tape-shaped metal foils cut into a width of 5 mm and two tapes of a dielectric film, and winding them. Both the foil and the dielectric film are being thinned as much as possible in response to the demands of the realization.

However, when metal foil such as aluminum foil (including alloy foil) is cut into a tape with a slitter, side edges of the foil become sharp angles in the thickness direction and burrs are generated at the same time. When they are wound together, they break through the thin dielectric film and cause a short circuit.

Further, during winding, the dielectric film and the metal foil tape are apt to be displaced in the width direction due to meandering, resulting in a large dimensional error, and it is necessary to make the width of the film sufficiently larger than that of the metal foil tape. Has become an obstacle.

Furthermore, when tightening the film and metal foil tape,
Wrinkles occur, which causes variations in electrostatic capacity and poor withstand voltage.

Furthermore, even if the capacitor element wound in a cylindrical shape is sandwiched between the hot plates and pressed to be flattened, the shape is maintained at the beginning, but there is a problem that it gradually recovers.

In addition, as an example, when winding up a pair of electrodes and a capacitor having an insulating dielectric structure, winding is performed by unwinding at least four coils of two coils of a dielectric film and two coils of a metal foil tape. Because it winds up,
It takes time to replace each of the four coils, and there is a problem that the operating rate of the device is reduced. Also, if the film or tape is broken, the operating rate is also reduced.
There is a limit to how thin these can be made, which is also an obstacle to miniaturization.

Therefore, after laminating the metal foil and the insulating material in advance, winding and tightening this, cutting it to an appropriate length and performing electrolytic corrosion treatment,
A method of removing the side edges of the metal foil to use it as an electrical component such as a capacitor is being considered (Japanese Patent Publication No. 45-38307).
Issue).

However, in the electrolytic corrosion treatment, since the metal foil serves as one electrode, the metal foil needs to have a certain thickness, for example, a thickness of 100 μm or more in order to attach the current-carrying terminal, which limits the miniaturization of the capacitor.

Further, the electrolytic corrosion processing method has a problem that a stable product cannot be obtained because the quality of the final product varies greatly with respect to the electrical performance.

Therefore, an object of the present invention is to provide a tape coil that is suitable for miniaturization and that can obtain a capacitor having a stable capacitance and a stable shape, and a method for manufacturing the same.

[Means for achieving the purpose]

In order to achieve the above object, the present invention comprises a coil formed by winding a tape having a dielectric film formed on one surface of a metal foil having a thickness of 5 μm or more, the tape comprising at least one side of the metal foil. It is characterized in that a margin is formed by chemically resolving the edge so that the edge is receded inward from the side edge of the dielectric film.

Further, in the manufacturing method, a dielectric film is integrally laminated on one or both sides of a metal foil raw sheet having a thickness of 5 μm or less,
A tape obtained by cutting this into an appropriate width is wound on a core to form a coil, and one end surface of the coil or the entire coil is immersed in a solution in which the metal foil is chemically dissolved, and the metal foil of the tape is The side edges were dissolved.

[Action]

By integrating the dielectric film and the extremely thin metal foil, the strength is increased, the wrinkles are eliminated, and burrs are removed at the same time by chemically dissolving the side edges of the metal foil. The side edges are smoothed and a margin of the dielectric film is formed.

〔Example〕

First, a method of manufacturing a tape for film capacitors will be described.

As shown in FIGS. 1 and 2, a wide aluminum foil 2 obtained by rewinding an aluminum foil original coil 1 having a thickness of 5 μm or less is coated with a resin by a roll 3 to form a dielectric film 4. It is dried in the drying zone 5 and wound on the coil 6.

The zone 5 may be an ultraviolet curing zone or an electron beam curing zone depending on the resin.

The resin may be a single or a mixture of vinyl-based, polyamide-based, polyolefin-based, polyester-based thermoplastic resins or the like, as well as an ultraviolet curable paint or an electron beam curable paint containing a prepolymer having a polymerizable functional group.

As shown in FIGS. 3 and 4, an aluminum foil 2 unwound from the original coil 1 is coated with an anchor coat 7 of urethane resin or the like by a roll 3 ', and then a thermoplastic resin is extruded from a nozzle 8. There is also a method in which the dielectric film 4 is formed, passed through a drying zone, and wound around the coil 6.

As the resin forming the film 4, polyethylene, polypropylene, polyester, polycarbonate, ionomer, Teflon, polyvinylidene fluoride or the like is used.

Further, as shown in FIGS. 5 and 6, an adhesive 7 ′ is applied to the unwound aluminum foil 2 by using a roll 3 ″, and a coil 9 of synthetic resin film is unwound and pressure-bonded. Alternatively, a method of forming the dielectric film 4 and winding it on the coil 6 may be used.

As the synthetic resin film, a single substance or a laminate of polyester, polycarbonate, polystyrene, polypropylene, polyethylene, ionomer, polyamide, polyvinylidene chloride, polyvinylidene fluoride, Teflon or the like is used. As the adhesive 7 ', for example, a urethane type adhesive is used.

In each of the above-mentioned methods, the example in which the dielectric film is formed on only one surface of the aluminum foil 2 has been shown, but it goes without saying that the dielectric film may be formed on both surfaces at the same time or may be formed on each surface separately.

Next, as shown in FIG. 7, the coil 6 of the aluminum foil 2 having the film 4 is rewound and cut with a slitter 9 to a predetermined width, for example, 3 to 30 mm to form a tape 10, which is coiled. Roll up to 11.

8 and 9 are sectional views of the tape 10. FIG. 8 shows the tape 10 with the coating 4 formed on one side, and FIG. 9 shows the tape 10 formed on both sides.

The coil 11 as described above is immersed in a solution 12 in which aluminum can be chemically dissolved, as shown in FIG.

As shown in FIG. 10, when the coil 11 is immersed so that it is completely immersed in the solution, the aluminum foil is dissolved from both end surfaces of the coil 11, and as shown in FIG. A margin 13 is formed by retreating inward from both side edges of No. 4. Tape 10 has film 4 on both sides as shown in Fig. 9.
When it has, the state becomes as shown in FIG.

If it is sufficient to melt only one side of the tape 10,
As shown in the figure, only one end surface of the coil 11 is immersed, or the other end surface is covered with a synthetic resin film or the like,
Soak the whole. Figure 14 shows the finished tape 10.

Examples of the solution for dissolving aluminum include an aqueous solution of caustic soda and an aqueous solution of ferric chloride. The concentration may be appropriately selected depending on the processing time and the like, and the temperature may be not only room temperature but also heating. The immersion time may be appropriately selected depending on the amount of the aluminum foil 2 dissolved, that is, the size of the margin 13.

After the dissolution treatment, of course, treatments such as washing with water, neutralization, rewashing with water, and drying are performed.

Two coils 11 obtained as described above are prepared, and these are stacked while being unwound, and further wound to form a capacitor element. 15 to 17 show a state of winding around the capacitor element. FIG. 15 shows the tape 10 of FIG. 12, FIG. 16 shows the tape 10 of FIG. 13, and FIG.
FIG. 14 shows a state where two tapes 0 in FIG. 14 are overlapped and wound.

 Hereinafter, experimental examples will be described.

[Experimental Example 1] A dielectric film made of a UV-curing resin having a thickness of 2μ was formed on both sides of an aluminum foil having a thickness of 4.5μ, and a tape cut to a width of 10 mm was wound to obtain a coil, and a liquid temperature was 60 ° C. It was immersed in a 1% aqueous solution of caustic soda for 1 minute. The coil was taken out, washed with water, immersed in a 2% dilute nitric acid aqueous solution for 1 minute, further taken out, washed with water and dried.

When the obtained coil was unwound, it could be smoothly unwound, and when the tape was observed with a stereomicroscope, there was no damage to the dielectric film, and both edges of the aluminum foil were smooth. However, about 0.1 mm was removed from each side edge of the dielectric film to form a uniform margin and no burr was observed.

[Experimental Example 2] A coil made of the same tape as in Experimental Example 1 and having a thickness of 4.5.
5μ thickness with adhesive on both sides of μ aluminum foil
A coil was prepared by laminating a polyester film prepared by laminating a dielectric film on a tape having a width of 10 mm and winding the tape.

The above two coils were immersed in a 20% aqueous solution of caustic soda having a liquid temperature of 60 ° C. for 5 minutes. These were taken out, washed with water, neutralized in a 2% dilute nitric acid aqueous solution, washed again with water, and then dried.

When the obtained coil was unwound, it could be smoothly unwound, and when the tape was observed with a stereoscopic microscope, there was no damage to the dielectric film, and both edges of the aluminum foil were smooth. However, 0.5 mm was removed from both edges of the dielectric film to form a uniform margin, and no burr was observed.

〔effect〕

According to the present invention, as described above, the aluminum foil and the dielectric film are laminated in advance, the tape is cut into a coil and wound into a coil, and the coil is immersed in a solution in which the metal foil is chemically dissolved. Since the side edges of the aluminum foil that will serve as the electrodes are melted, the side edges are melted smoothly and the burr is completely removed, and when the tape coil is rewound, it can be smoothly wound. It is returned and does not damage the dielectric film.

Also, since an extremely thin metal foil can be used,
The capacitor can be downsized.

Further, since the tape coil, which is the material of the capacitor, is formed in advance, it is possible to obtain a capacitor with stable electrical characteristics and good quality by adjusting the number of windings etc. by knowing the characteristics of the material.

[Brief description of drawings]

FIG. 1 is a side view showing a step of forming a dielectric film on an aluminum foil, FIG. 2 is a sectional view of a laminate obtained by the same as above, and FIG. 3 is a side view showing a step different from FIG. Line part,
FIG. 4 is a sectional view of the laminated body obtained by the same as above, FIG. 5 is a side view showing another step different from FIG. 1, and FIG. 6 is a sectional view of the laminated body obtained by the same as above. FIG. 7 is a perspective view showing a process for producing a tape from the above laminated body, FIGS. 8 and 9 are sectional views of the obtained tape, FIGS. 10 and 11.
The figure is a cross-sectional view showing the process of melting the aluminum foil side edge of the tape, FIGS. 12 to 14 are cross-sectional views of the tape obtained by the same as above, and FIGS. 15 to 17 are the same tape as a capacitor element. It is sectional drawing which shows the wound state. 1 ... Aluminum foil original coil, 2 ... Aluminum foil, 3,3 ', 3 "... Roll, 4 ... Dielectric film, 6 ...
… Laminated coil, 10 …… Tape, 11 …… Tape coil, 12 …… Soluble aluminum solution, 13 …… Margin.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshihiko Nakano 1 Toyo Aluminum Co., Ltd., 4-25, Minamikyutaro-cho, Higashi-ku, Osaka-shi, Osaka (56) References JP-B-45-38307 (JP, B1) Special Public Sho 43-3660 (JP, B1)

Claims (2)

[Claims] 1. A coil formed by winding a tape having a dielectric film formed on one surface of a metal foil having a thickness of 5 μm or less, the tape being formed by chemically dissolving at least one side edge of the metal foil. A material tape coil for a film capacitor, characterized in that a margin is formed on the side edge of the dielectric film. 2. A metal foil having a thickness of 5 μm or less, on one or both sides of which a dielectric film is integrally laminated, and cut into a suitable width to wind a tape to form a coil. A method for manufacturing a material tape coil of a film capacitor, which comprises immersing at least one end surface of the coil in a solution which is chemically dissolved, and dissolving at least one side edge of the metal foil of the tape.